An Investigation of Microstructural Evolution, Tensile Properties and Work-Hardening Behavior of Nanosized TiB₂/Al-Cu-Mn Composites

The microstructure evolution, tensile properties and work-hardening behavior of AA2219 alloy reinforced by in situ nanosized TiB₂ particles were studied in this paper. The observation indicated an impeded recrystallization of the matrix alloy by nanosized TiB₂ particles, and the hybrids of nanosized TiB₂ particles and Al₂Cu phases located at the grain boundary hindered the grain growth. Meanwhile, a large amount fiber textures of <111>//RD (Rolling direction), <110>//RD, <100>//RD <111>//ND (Normal direction), <110>//ND and <100>//ND were detected in nanosized TiB₂/AA2219 composite. Tensile test results exhibited a combination of good strength and ductility of the present composite whose yield strength and tensile strength were 11.4% and 5.8% higher than those of the alloy, while its fracture strain increased slightly. Meanwhile, the correlation between this modified microstructure of nanosized TiB₂ particles and comprehensive mechanical properties was established. This study provides a new insight into the fabrication and strengthening behaviors of Al matrix composites reinforced by in situ nanoparticles.