Effect of HEA/Al composite interlayer on microstructure and mechanical property of Ti/Mg bimetal composite by solid-liquid compound casting

In this study, HEA/Al composite interlayer was used to fabricate Ti/Mg bimetal composites by solid-liquid compound casting process. The Al layer was prepared on the surface of TC4 alloy by hot dipping, and the FeCoNiCr HEA layer was prepared by magnetron sputtering onto the Al layer. The influence of the HEA layer thickness and pouring temperature on interface evolution was investigated based on SEM observation and thermodynamic analysis. Results indicate that the sluggish diffusion effect of HEA can effectively inhibit the interfacial diffusion between Al and Mg, which is conducive to the formation of solid solution, especially when the thickness of HEA is 800 nm. With the increase of casting temperature from 720 degrees C to 730 degrees C, 740 degrees C, and 750 degrees C, alpha-Al(Mg), alpha-Al(Mg)+Al3Mg2, Al3Mg2+Al12Mg17, and Al12Mg17+delta-Mg are formed at the interface of Ti/Mg bimetal, respectively. When the thickness of the HEA layer is 800 nm and the pouring temperature is 720 degrees C, the bonding strength of the Ti/Mg bimetal can reach the maximum of 93.6 MPa.