**Si Gao 1,\*, Takuma Yoshimura 1, Wenqi Mao 1, Yu Bai 1, Wu Gong 2,3, Myeong-heom Park 2, Akinobu Shibata 1,2, Hiroki Adachi 4, Masugu Sato <sup>5</sup> and Nobuhiro Tsuji 1,2**


Received: 6 October 2020; Accepted: 3 December 2020; Published: 7 December 2020

**Abstract:** Intermetallic compounds are usually considered as deleterious phase in alloy designing and processing since their brittleness leads to poor ductility and premature failure during deformation of the alloys. However, several studies recently found that some alloys containing large amounts of NiAl-type intermetallic particles exhibited not only high strength but also good tensile ductility. To clarify the role of the intermetallic particles in the excellent tensile properties of such alloys, the tensile deformation behavior of an ultrafine-grained Fe-Mn-Al-Ni-C alloy containing austenite matrix and B2 intermetallic particles was investigated by using in situ synchrotron radiation X-ray diffraction in the present study. The elastic stress partitioning behavior of two constituent phases during tensile deformation were quantitively measured, and it was suggested that B2 particles played an important role in the high strength and large tensile ductility of the material.

**Keywords:** ultrafine-grained materials; intermetallic compounds; B2 phase; strain hardening behavior; synchrotron radiation X-ray diffraction
