materials-logo

Journal Browser

Journal Browser

Structure and Mechanical Properties of Transition Group Metals, Alloys, and Intermetallic Compounds

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (5 March 2019) | Viewed by 52966

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editor

Department of Advanced Materials and Technologies, Faculty of Advanced Technologies and Chemistry, Military University of Technology, Gen. S. Kaliskiego 2, 00-908 Warsaw, Poland
Interests: microstructural characterization; nonferrous alloys (Al, Ti, Mg, etc.); intermetallics; additive manufacturing; hydrogen storage
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Mechanical properties of polycrystalline structural materials, such as metals, alloys and intermetallic compounds, are significantly affected by their microstructures, including phase composition, grain shape and size, grain boundary distribution, dislocation density, dispersed particles and solutes, internal stresses, etc. Therefore, studies on the relationships between microstructure and mechanical properties are of a great practical importance. The development of metallic/intermetallic constructive materials with desired structures results in beneficial combinations of mechanical properties. Various thermo-mechanical treatments are widely used to produce metallic materials with preferred microstructures, achieved owing to diverse mechanisms of evolution. Knowledge regarding the effect of applied techniques and processing windows on the structural changes in metals, alloys and intermetallic compounds provides the development of manufacturing methods of structural materials with enhanced mechanical properties. The aim of this Special Issue is to present the latest achievements in theoretical and experimental investigations of mechanisms of microstructural changes in various metallic materials subjected to different processing methods, as well as their effect on mechanical properties. In conclusion, it is my pleasure to invite all researchers from the community of transition group metals, alloys, and intermetallic compounds to submit a manuscript in the field for this Special Issue.

Prof. Tomasz Czujko
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  •  Structural steels and alloys
  •  Intermetallic compounds
  •  Deformation and annealing behavior
  •  Microstructure and texture
  •  Static/dynamic recovery and recrystallization
  •  Strengthening mechanisms
  •  Mechanical properties.

Published Papers (15 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

12 pages, 8344 KiB  
Article
In Situ Study on Fracture Behavior of Z-Pinned Carbon Fiber-Reinforced Aluminum Matrix Composite via Scanning Electron Microscope (SEM)
by Yunhe Zhang, Sian Wang, Xiwang Zhao, Fanming Wang and Gaohui Wu
Materials 2019, 12(12), 1941; https://doi.org/10.3390/ma12121941 - 17 Jun 2019
Cited by 7 | Viewed by 2281
Abstract
Inside a scanning electron microscope (SEM) chamber, we performed an in situ interlaminar shear test on a z-pinned carbon fiber-reinforced aluminum matrix composite (Cf/Al) fabricated by the pressure the infiltration method to understand its failure mechanism. Experiments show that introducing a stainless-steel z-pin [...] Read more.
Inside a scanning electron microscope (SEM) chamber, we performed an in situ interlaminar shear test on a z-pinned carbon fiber-reinforced aluminum matrix composite (Cf/Al) fabricated by the pressure the infiltration method to understand its failure mechanism. Experiments show that introducing a stainless-steel z-pin increases the interlaminar shear strength of Cf/Al composite by 148%. The increase in interlaminar shear strength is attributed to the high strength of the stainless-steel z-pin and the strong bonding between the z-pin and the matrix. When the z-pin/matrix interface failed, the z-pin can still experience large shear deformation, thereby enhancing delamination resistance. The failure mechanism of composite includes interfacial debonding, aluminum plough, z-pin shear deformation, frictional sliding, and fracture. These results in this study will help us understand the interlaminar strengthening mechanism of z-pins in the delamination of metal matrix composites. Full article
Show Figures

Figure 1

13 pages, 4405 KiB  
Article
The Tribaloy T-800 Coatings Deposited by Laser Engineered Net Shaping (LENSTM)
by Tomasz Durejko, Magdalena Łazińska, Julita Dworecka-Wójcik, Stanisław Lipiński, Robert A. Varin and Tomasz Czujko
Materials 2019, 12(9), 1366; https://doi.org/10.3390/ma12091366 - 26 Apr 2019
Cited by 19 | Viewed by 3401
Abstract
A Tribaloy family of alloys (CoMoCrSi) are characterized by a substantial resistance to wear and corrosion within a wide range of temperatures. These properties are a direct result of their microstructure including the presence of Laves phase in varying proportions. Tribaloy T-800 exhibits [...] Read more.
A Tribaloy family of alloys (CoMoCrSi) are characterized by a substantial resistance to wear and corrosion within a wide range of temperatures. These properties are a direct result of their microstructure including the presence of Laves phase in varying proportions. Tribaloy T-800 exhibits the highest content of Laves phase of all other commercial Tribaloy alloys, which provides high hardness and wear resistance. On the other hand, a large content of the Laves phase brings about a high sensitivity to brittle fracture of this alloy. The main objective of this work was a development of the Tribaloy T-800 coatings on the Ni-based superalloy substrate (RENE 77), which employs a Laser Engineered Net Shaping (LENSTM) technique. Technological limitations in this process are susceptibility of T-800 to brittle fracture as well as significant thermal stresses due to rapid cooling, which is an inherent attribute of laser techniques. Therefore, in this work, a number of steps that optimized the LENSTM process and improved the metallurgical soundness of coatings are presented. Employing volume and local substrate pre-heating resulted in the formation of high quality coatings devoid of cracks and flaws. Full article
Show Figures

Figure 1

16 pages, 5713 KiB  
Article
Structure and Deformation Behavior of Ti-SiC Composites Made by Mechanical Alloying and Spark Plasma Sintering
by Dariusz Garbiec, Volf Leshchynsky, Alberto Colella, Paolo Matteazzi and Piotr Siwak
Materials 2019, 12(8), 1276; https://doi.org/10.3390/ma12081276 - 18 Apr 2019
Cited by 7 | Viewed by 2431
Abstract
Combining high energy ball milling and spark plasma sintering is one of the most promising technologies in materials science. The mechanical alloying process enables the production of nanostructured composite powders that can be successfully spark plasma sintered in a very short time, while [...] Read more.
Combining high energy ball milling and spark plasma sintering is one of the most promising technologies in materials science. The mechanical alloying process enables the production of nanostructured composite powders that can be successfully spark plasma sintered in a very short time, while preserving the nanostructure and enhancing the mechanical properties of the composite. Composites with MAX phases are among the most promising materials. In this study, Ti/SiC composite powder was produced by high energy ball milling and then consolidated by spark plasma sintering. During both processes, Ti3SiC2, TiC and Ti5Si3 phases were formed. Scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction study showed that the phase composition of the spark plasma sintered composites consists mainly of Ti3SiC2 and a mixture of TiC and Ti5Si3 phases which have a different indentation size effect. The influence of the sintering temperature on the Ti-SiC composite structure and properties is defined. The effect of the Ti3SiC2 MAX phase grain growth was found at a sintering temperature of 1400–1450 °C. The indentation size effect at the nanoscale for Ti3SiC2, TiC+Ti5Si3 and SiC-Ti phases is analyzed on the basis of the strain gradient plasticity theory and the equation constants were defined. Full article
Show Figures

Figure 1

10 pages, 4770 KiB  
Article
Effects of Thermal Variables of Solidification on the Microstructure, Hardness, and Microhardness of Cu-Al-Ni-Fe Alloys
by Maurício Silva Nascimento, Givanildo Alves dos Santos, Rogério Teram, Vinícius Torres dos Santos, Márcio Rodrigues da Silva and Antonio Augusto Couto
Materials 2019, 12(8), 1267; https://doi.org/10.3390/ma12081267 - 18 Apr 2019
Cited by 17 | Viewed by 3973
Abstract
Aluminum bronze is a complex group of copper-based alloys that may include up to 14% aluminum, but lower amounts of nickel and iron are also added, as they differently affect alloy characteristics such as strength, ductility, and corrosion resistance. The phase transformations of [...] Read more.
Aluminum bronze is a complex group of copper-based alloys that may include up to 14% aluminum, but lower amounts of nickel and iron are also added, as they differently affect alloy characteristics such as strength, ductility, and corrosion resistance. The phase transformations of nickel aluminum–bronze alloys have been the subject of many studies due to the formations of intermetallics promoted by slow cooling. In the present investigation, quaternary systems of aluminum bronze alloys, specifically Cu–10wt%Al–5wt%Ni–5wt%Fe (hypoeutectoid bronze) and Cu–14wt%Al–5wt%Ni–5wi%Fe (hypereutectoid bronze), were directionally solidified upward under transient heat flow conditions. The experimental parameters measured included solidification thermal parameters such as the tip growth rate (VL) and cooling rate (TR), optical microscopy, scanning electron microscopy (SEM) analysis, hardness, and microhardness. We observed that the hardness and microhardness values vary according to the thermal parameters and solidification. We also observed that the Cu–14wt%Al–5wt%Ni–5wi%Fe alloy presented higher hardness values and a more refined structure than the Cu–10wt%Al–5wt%Ni–5wt%Fe alloy. SEM analysis proved the presence of specific intermetallics for each alloy. Full article
Show Figures

Figure 1

20 pages, 24618 KiB  
Article
Static and Dynamic Loading Behavior of Ti6Al4V Honeycomb Structures Manufactured by Laser Engineered Net Shaping (LENSTM) Technology
by Anna Antolak-Dudka, Paweł Płatek, Tomasz Durejko, Paweł Baranowski, Jerzy Małachowski, Marcin Sarzyński and Tomasz Czujko
Materials 2019, 12(8), 1225; https://doi.org/10.3390/ma12081225 - 15 Apr 2019
Cited by 54 | Viewed by 5337
Abstract
Laser Engineered Net Shaping (LENSTM) is currently a promising and developing technique. It allows for shortening the time between the design stage and the manufacturing process. LENS is an alternative to classic metal manufacturing methods, such as casting and plastic working. [...] Read more.
Laser Engineered Net Shaping (LENSTM) is currently a promising and developing technique. It allows for shortening the time between the design stage and the manufacturing process. LENS is an alternative to classic metal manufacturing methods, such as casting and plastic working. Moreover, it enables the production of finished spatial structures using different types of metallic powders as starting materials. Using this technology, thin-walled honeycomb structures with four different cell sizes were obtained. The technological parameters of the manufacturing process were selected experimentally, and the initial powder was a spherical Ti6Al4V powder with a particle size of 45–105 µm. The dimensions of the specimens were approximately 40 × 40 × 10 mm, and the wall thickness was approximately 0.7 mm. The geometrical quality and the surface roughness of the manufactured structures were investigated. Due to the high cooling rates occurring during the LENS process, the microstructure for this alloy consists only of the martensitic α’ phase. In order to increase the mechanical parameters, it was necessary to apply post processing heat treatment leading to the creation of a two-phase α + β structure. The main aim of this investigation was to study the energy absorption of additively manufactured regular cellular structures with a honeycomb topology under static and dynamic loading conditions. Full article
Show Figures

Figure 1

15 pages, 6047 KiB  
Article
Microstructure and Hot Deformation Behavior of Twin Roll Cast Mg-2Zn-1Al-0.3Ca Alloy
by Kristina Kittner, Madlen Ullmann, Thorsten Henseler, Rudolf Kawalla and Ulrich Prahl
Materials 2019, 12(7), 1020; https://doi.org/10.3390/ma12071020 - 28 Mar 2019
Cited by 12 | Viewed by 2928
Abstract
In the present work, the microstructure, texture, mechanical properties as well as hot deformation behavior of a Mg-2Zn-1Al-0.3Ca sheet manufactured by twin roll casting were investigated. The twin roll cast state reveals a dendritic microstructure with intermetallic compounds predominantly located in the interdendritic [...] Read more.
In the present work, the microstructure, texture, mechanical properties as well as hot deformation behavior of a Mg-2Zn-1Al-0.3Ca sheet manufactured by twin roll casting were investigated. The twin roll cast state reveals a dendritic microstructure with intermetallic compounds predominantly located in the interdendritic areas. The twin roll cast samples were annealed at 420 °C for 2 h followed by plane strain compression tests in order to study the hardening and softening behavior. Annealing treatment leads to the formation of a grain structure, consisting of equiaxed grains with an average diameter of approximately 19 µm. The twin roll cast state reveals a typical basal texture and the annealed state shows a weakened texture, by spreading basal poles along the transverse direction. The twin roll cast Mg-2Zn-1Al-0.3Ca alloy offers a good ultimate tensile strength of 240 MPa. The course of the flow curves indicate that dynamic recrystallization occurs during hot deformation. For the validity range from 250 °C to 450 °C as well as equivalent logarithmic strain rates from 0.01 s−1 to 10 s−1 calculated model coefficients are shown. The average activation energy for plastic flow of the twin roll cast and annealed Mg-2Zn-1Al-0.3Ca alloy amounts to 180.5 kJ/mol. The processing map reveals one domain with flow instability at temperatures above 370 °C and strain rates ranging from 3 s−1 to 10 s−1. Under these forming conditions, intergranular cracks arose and grew along the grain boundaries. Full article
Show Figures

Figure 1

19 pages, 14858 KiB  
Article
Identification of Mechanical Properties for Titanium Alloy Ti-6Al-4V Produced Using LENS Technology
by Aleksandra Szafrańska, Anna Antolak-Dudka, Paweł Baranowski, Paweł Bogusz, Dariusz Zasada, Jerzy Małachowski and Tomasz Czujko
Materials 2019, 12(6), 886; https://doi.org/10.3390/ma12060886 - 16 Mar 2019
Cited by 24 | Viewed by 3904
Abstract
This paper presents a characterization study of specimens manufactured from Ti-6Al-4V powder with the use of laser engineered net shaping technology (LENS). Two different orientations of the specimens were considered to analyze the loading direction influence on the material mechanical properties. Moreover, two [...] Read more.
This paper presents a characterization study of specimens manufactured from Ti-6Al-4V powder with the use of laser engineered net shaping technology (LENS). Two different orientations of the specimens were considered to analyze the loading direction influence on the material mechanical properties. Moreover, two sets of specimens, as-built (without heat treatment) and after heat treatment, were used. An optical measurement system was also adopted for determining deformation of the specimen, areas of minimum and the maximum principal strain, and an effective plastic strain value at failure. The loading direction dependence on the material properties was observed with a significant influence of the orientation on the stress and strain level. Microstructure characterization was examined with the use of optical and scanning electron microscopes (SEM); in addition, the electron backscatter diffraction (EBSD) was also used. The fracture mechanism was discussed based on the fractography analysis. The presented comprehensive methodology proved to be effective and it could be implemented for different materials in additive technologies. The material data was used to obtain parameters for the selected constitutive model to simulate the energy absorbing structures manufactured with LENS technology. Therefore, a brief discussion related to numerical modelling of the LENS Ti-6Al-4V alloy was also included in the paper. The numerical modelling confirmed the correctness of the acquired material data resulting in a reasonable reproduction of the material behavior during the cellular structure deformation process. Full article
Show Figures

Figure 1

11 pages, 6407 KiB  
Article
Strain Rate during Creep in High-Pressure Die-Cast AZ91 Magnesium Alloys at Intermediate Temperatures
by Mónica Preciado, Pedro M. Bravo, José Calaf and Daniel Ballorca
Materials 2019, 12(6), 872; https://doi.org/10.3390/ma12060872 - 15 Mar 2019
Cited by 2 | Viewed by 2811
Abstract
During creep, magnesium alloys undergo microstructural changes due to temperature and stress. These alterations are associated with the evolution of the present phases at a microstructural level, creating different strain rates during primary and tertiary creep, and with the stability of the inter-metallic [...] Read more.
During creep, magnesium alloys undergo microstructural changes due to temperature and stress. These alterations are associated with the evolution of the present phases at a microstructural level, creating different strain rates during primary and tertiary creep, and with the stability of the inter-metallic phase Mg17Al12 formed at these temperatures. In this paper, the results of creep testing of high-pressure die-cast AZ91 magnesium alloys are reported. During creep, continuous and discontinuous precipitates grow, which influences creep resistance. The creep mechanism that acts at these intermediate temperatures up to 150 °C is termed dislocation climbing. Finally, the influence of the type of precipitates on the creep behavior of alloys is determined by promoting the formation of continuous precipitates by a short heat treatment prior to creep testing. Full article
Show Figures

Figure 1

17 pages, 12431 KiB  
Article
The Influence of Post-Weld Heat Treatment on the Microstructure and Fatigue Properties of Sc-Modified AA2519 Friction Stir-Welded Joint
by Robert Kosturek, Lucjan Śnieżek, Marcin Wachowski and Janusz Torzewski
Materials 2019, 12(4), 583; https://doi.org/10.3390/ma12040583 - 15 Feb 2019
Cited by 25 | Viewed by 3236
Abstract
The aim of this research was to investigate the influence of post-weld heat treatment (PWHT, precipitation hardening) on the microstructure and fatigue properties of an AA2519 joint obtained in a friction stir-welding process. The welding process was performed with three sets of parameters. [...] Read more.
The aim of this research was to investigate the influence of post-weld heat treatment (PWHT, precipitation hardening) on the microstructure and fatigue properties of an AA2519 joint obtained in a friction stir-welding process. The welding process was performed with three sets of parameters. One part of the obtained joints was investigated in the as-welded state and the second part of joints was subjected to the post-weld heat treatment (precipitation hardening) and then investigated. In order to establish the influence of the heat treatment on the microstructure of obtained joints both light and scanning electron microscopy observations were performed. Additionally, microhardness analysis for each sample was carried out. Fatigue properties of the samples in the as-welded state and the samples after post-weld heat treatment were established in a low-cycle fatigue test with constant true strain amplitude equal to ε = 0.25% and cycle asymmetry coefficient R = 0.1. Hysteresis loops together with changes of stress and plastic strain versus number of cycles are presented in this paper. The fatigue fracture in tested samples was analyzed with the use of scanning electron microscope. Our results show that post-weld heat treatment of AA2519 friction stir-welded joints significantly decreases their fatigue life. Full article
Show Figures

Graphical abstract

12 pages, 3404 KiB  
Article
Dissolution of Ag Precipitates in the Cu–8wt.%Ag Alloy Deformed by High Pressure Torsion
by Anna Korneva, Boris Straumal, Askar Kilmametov, Robert Chulist, Grzegorz Cios, Brigitte Baretzky and Paweł Zięba
Materials 2019, 12(3), 447; https://doi.org/10.3390/ma12030447 - 01 Feb 2019
Cited by 15 | Viewed by 3437
Abstract
The aim of this work was to study the influence of severe plastic deformation (SPD) on the dissolution of silver particles in Cu–8wt.%Ag alloys. In order to obtain different morphologies of silver particles, samples were annealed at 400, 500 and 600 °C. Subsequently, [...] Read more.
The aim of this work was to study the influence of severe plastic deformation (SPD) on the dissolution of silver particles in Cu–8wt.%Ag alloys. In order to obtain different morphologies of silver particles, samples were annealed at 400, 500 and 600 °C. Subsequently, the material was subjected to high pressure torsion (HPT) at room temperature. By means of scanning and transmission electron microscopy, as well as X-ray diffraction techniques, it was found that during SPD, the dissolution of second phase was strongly affected by the morphology and volume fraction of the precipitates in the initial state. Small, heterogeneous precipitates of irregular shape dissolved more easily than those of large size, round-shaped and uniform composition. It was also found that HPT led to the increase of solubility limit of silver in the copper matrix as the result of dissolution of the second phase. This unusual phase transition is discussed with respect to diffusion activation energy and mixing enthalpy of the alloying elements. Full article
Show Figures

Figure 1

11 pages, 2342 KiB  
Article
Structural and Mechanical Properties of Ti–Co Alloys Treated by High Pressure Torsion
by Boris B. Straumal, Anna Korneva, Askar R. Kilmametov, Lidia Lityńska-Dobrzyńska, Alena S. Gornakova, Robert Chulist, Mikhail I. Karpov and Paweł Zięba
Materials 2019, 12(3), 426; https://doi.org/10.3390/ma12030426 - 30 Jan 2019
Cited by 23 | Viewed by 4195
Abstract
The microstructure and properties of titanium-based alloys can be tailored using severe plastic deformation. The structure and microhardness of Ti–4 wt.% Co alloy have been studied after preliminary annealing and following high pressure torsion (HPT). The Ti–4 wt.% Co alloy has been annealed [...] Read more.
The microstructure and properties of titanium-based alloys can be tailored using severe plastic deformation. The structure and microhardness of Ti–4 wt.% Co alloy have been studied after preliminary annealing and following high pressure torsion (HPT). The Ti–4 wt.% Co alloy has been annealed at 400, 500, and 600 °C, i.e., below the temperature of eutectoid transformation in the Ti–4 wt.% Co system. The amount of Co dissolved in α-Ti increased with increasing annealing temperature. HPT led to the transformation of α-Ti in ω-Ti. After HPT, the amount of ω-phase in the sample annealed at 400 °C was about 80­85%, i.e., higher than in pure titanium (about 40%). However, with increasing temperature of pre-annealing, the portion of ω-phase decreased (60–65% at 500 °C and about 5% at 600 °C). The microhardness of all investigated samples increased with increasing temperature of pre-annealing. Full article
Show Figures

Figure 1

11 pages, 4485 KiB  
Article
Microstructure and Flexural Properties of Z-Pinned Carbon Fiber-Reinforced Aluminum Matrix Composites
by Sian Wang, Yunhe Zhang, Pibo Sun, Yanhong Cui and Gaohui Wu
Materials 2019, 12(1), 174; https://doi.org/10.3390/ma12010174 - 07 Jan 2019
Cited by 12 | Viewed by 3348
Abstract
Z-pinning can significantly improve the interlaminar shear properties of carbon fiber-reinforced aluminum matrix composites (Cf/Al). However, the effect of the metal z-pin on the in-plane properties of Cf/Al is unclear. This study examines the effect of the z-pin on the flexural strength and [...] Read more.
Z-pinning can significantly improve the interlaminar shear properties of carbon fiber-reinforced aluminum matrix composites (Cf/Al). However, the effect of the metal z-pin on the in-plane properties of Cf/Al is unclear. This study examines the effect of the z-pin on the flexural strength and failure mechanism of Cf/Al composites with different volume contents and diameters of the z-pins. The introduction of a z-pin leads to the formation of a brittle phase at the z-pin/matrix interface and microstructural damage such as aluminum-rich pockets and carbon fiber waviness, thereby resulting in a reduction of the flexural strength. The three-point flexural test results show that the adding of a metal z-pin results in reducing the Cf/Al composites’ flexural strength by 2–25%. SEM imaging of the fracture surfaces revealed that a higher degree of interfacial reaction led to more cracks on the surface of the z-pin. This crack-susceptible interface layer between the z-pin and the matrix is likely the primary cause of the reduction of the flexural strength. Full article
Show Figures

Figure 1

17 pages, 6760 KiB  
Article
Severe Plastic Deformation of Fe-22Al-5Cr Alloy by Cross-Channel Extrusion with Back Pressure
by Radosław Łyszkowski, Wojciech Polkowski and Tomasz Czujko
Materials 2018, 11(11), 2214; https://doi.org/10.3390/ma11112214 - 08 Nov 2018
Cited by 8 | Viewed by 2585
Abstract
A new concept of the cross-channel extrusion (CCE) process under back pressure (BP) was proposed and tested experimentally. The obtained by finite element method (FEM) results showed that a triaxial compression occurred in the central zone, whereas the material was deformed by shearing [...] Read more.
A new concept of the cross-channel extrusion (CCE) process under back pressure (BP) was proposed and tested experimentally. The obtained by finite element method (FEM) results showed that a triaxial compression occurred in the central zone, whereas the material was deformed by shearing in the outer zone. This led to the presence of a relatively uniformly deformed outer zone at 1 per pass and a strong deformation of the paraxial zone (3–5/pass). An increase in the BP did not substantially affect the accumulated strain but made it more uniform. The FEM results were verified using the physical modeling technique (PMT) by the extrusion of clay billet. The formation of the plane of the strongly flattened, and elongated grains were observed in the extrusion directions. With the increase in the number of passes, the shape of the resulting patterns expanded, indicating an increase in the deformation homogeneity. Finally, these investigations were verified experimentally for Fe-22Al-5Cr (at. %) alloy using of the purposely designed tooling. The effect of the CCE process is the fragmentation of the original material structure by dividing the primary grains. The complexity of the stress state leads to the rapid growth of microshear bands (MSB), grain defragmentation and the nucleation of new dynamically recrystallized grains about 200–400 nm size. Full article
Show Figures

Graphical abstract

14 pages, 2498 KiB  
Article
Interlaminar Shear Properties of Z-Pinned Carbon Fiber Reinforced Aluminum Matrix Composites by Short-Beam Shear Test
by Sian Wang, Yunhe Zhang and Gaohui Wu
Materials 2018, 11(10), 1874; https://doi.org/10.3390/ma11101874 - 01 Oct 2018
Cited by 13 | Viewed by 4327
Abstract
This paper presents the effect of through-thickness reinforcement by steel z-pins on the interlaminar shear properties and strengthening mechanisms of carbon fiber reinforced aluminum matrix composites (Cf/Al) with a short beam shear test method. Microstructural analysis reveals that z-pins cause minor microstructural damage [...] Read more.
This paper presents the effect of through-thickness reinforcement by steel z-pins on the interlaminar shear properties and strengthening mechanisms of carbon fiber reinforced aluminum matrix composites (Cf/Al) with a short beam shear test method. Microstructural analysis reveals that z-pins cause minor microstructural damage including to fiber waviness and aluminum-rich regions, and interface reaction causes a strong interface between the stainless steel pin and the aluminum matrix. Z-pinned Cf/Al composites show reduced apparent interlaminar shear strength due to a change in the failure mode compared to unpinned specimens. The changed failure mode could result from decreased flexural strength due to microstructural damage as well as increased actual interlaminar shear strength. Fracture work is improved significantly with a z-pin diameter. The strong interface allows the deformation resistance of the steel pin to contribute to the crack bridging forces, which greatly enhances the interlaminar shear properties. Full article
Show Figures

Figure 1

12 pages, 5955 KiB  
Article
Grain-Boundary Interaction between Inconel 625 and WC during Laser Metal Deposition
by Jan Huebner, Dariusz Kata, Paweł Rutkowski, Paweł Petrzak and Jan Kusiński
Materials 2018, 11(10), 1797; https://doi.org/10.3390/ma11101797 - 21 Sep 2018
Cited by 13 | Viewed by 3843
Abstract
In this study, the laser metal deposition (LMD) of the Inconel 625–tungsten carbide (WC) metal matrix composite was investigated. The composite coating was deposited on Inconel 625 substrate by powder method. A powder mixture containing 10 wt% of WC (5 µm) was prepared [...] Read more.
In this study, the laser metal deposition (LMD) of the Inconel 625–tungsten carbide (WC) metal matrix composite was investigated. The composite coating was deposited on Inconel 625 substrate by powder method. A powder mixture containing 10 wt% of WC (5 µm) was prepared by wet mixing with dextrin binder. Coating samples obtained by low-power LMD were pore- and crack-free. Ceramic reinforcement was distributed homogenously in the whole volume of the material. Topologically close-packed (TCP) phases were formed at grain boundaries between WC and Inconel 625 matrix as a result of partial dissolution of WC in a nickel-based alloy. Line analysis of the elements revealed very small interference of the coating in the substrate material when compared to conventional coating methods. The average Vickers hardness of the coating was about 25% higher than the hardness of pure Inconel 625 reference samples. Full article
Show Figures

Figure 1

Back to TopTop