**4. Conclusions**

In this work, the continuous casting performance of AZ91D and A5052 was verified by single-roll casting experiments, and the experimental solidification constants of AZ91D and A5052 were obtained by empirical equations and fitted curves, with values of 62 mm/min0.5 and 34 mm/min0.5, respectively. Next, the surface temperatures of the metals during singleroll casting were measured to provide data to support the subsequent temperature change discussion of the bonding interface during double-roll composite casting. In addition, for continuous casting of a small number of metal ingots, the surface temperature variations of the casting rolls could be neglected.

Furthermore, the AZ91D/A5052 clad strips were successfully fabricated by direct cladding from molten metals using a horizontal twin-roll caster. The optimal experimental parameters were investigated by conducting tests under different experimental conditions of roll speed, pouring sequence, and solidification length. The results showed that the AZ91D/A5052 clad strip with a thickness of 4.9 mm was successfully cast at a rolling speed of 9 m/min and rolling gap of 5 mm. We found that the roll speed affected the surface state of A5052 on the lower roll side more than AZ91D on the upper roll side. In addition, the casting sequence of AZ91D/A5052 (upper nozzle metal/lower nozzle metal) made it easier to form the strip compared to A5052/AZ91D, and the intermetallic compounds produced at the bonding interface of AZ91D and A5052 could be controlled by the upper solidification length. The cross-section (Figure 9) showed that the AZ91D/A5052 strip had a cladding ratio of approximately 1:1, while three intermetallic compound layers were found at the bonding interface. Finally, the use of a horizontal twin-roll caster allowed for the direct compounding of dissimilar metals.

**Author Contributions:** Writing—original draft preparation, G.F.; conceptualization, T.H. and H.W.; methodology, G.F. and H.W.; investigation, G.F.; resources, H.W.; validation, G.F. and H.W.; data curation, G.F. and H.W.; writing—review and editing, G.F. and H.W.; All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
