Effect of Pack Rolling and Heat Treatment on Microstructure and Mechanical Properties of B₄C_P/6061Al Composite Prepared by Powder Metallurgy

This study aims to investigate the effect of hot pack rolling and T6 heat treatment on microstructure and mechanical properties of 25 vol% B₄C_P/6061Al composite fabricated by powder metallurgy. Results show that hot pack rolling process could break the particle agglomeration, refine grain size, decrease porosity and improve the interface bonding quality. Almost 15%, 21% and 328% improvement in ultimate tensile strength, yield strength and elongation for B₄C_P/6061Al composite were obtained after hot pack rolling. It was also found that the average grain size increased due to the static recrystallization during the T6 heat treatment process. XRD patterns revealed that Mg₂Si precipitation hardening phase was formed in the matrix. Compared with the rolled B₄C_P/6061Al composite, T6 heat treatment resulted in improving the ultimate tensile strength, yield strength and elongation by 7%, 11% and 50%. The strengthening mechanisms and fractured surfaces under different stages were also discussed.

The hot pack rolling process could break the particle agglomeration, refine grain size, decrease porosity and improve the interface bonding quality. The properties test indicates that almost 15%, 21% and 328% improvement in ultimate tensile strength, yield strength and elongation for B4CP/6061Al composite were obtained after hot pack rolling. Compared with the roll-ed B4CP/6061Al composite, T6 heat treatment resulted in improving the ultimate tensile strength, yield strength and elongation by 7%, 11% and 50%.