Thermal effect of quench rate on mechanical properties of SIMA 7075-T6

Abstract

In this study, thermal effects of quench rate on mechanical properties of 7075-T6 alloy fabricated by strain induced melt activation (SIMA) process were investigated. The T6 heat treatments were applied in various parameters after SIMA: solutionizing at 490?C for 15-30-45-60-120 minutes, quenching at 60-100?C, and aging at 120?C for 12-24-48 hours. Optical and SEM analyses were performed for characterization, hardness, and tensile tests for mechanical evaluation. Analysis of variance tests was carried out to indicate the validity of the interactions quenching temperatures and tensile properties. Secondary phases were dissolved homogeneously after solutionizing but at higher quenching temperatures and reprecipitated, particularly at grain boundaries. Strength values decreased with increasing quenching temperature. Analysis of variance tests suggest that cryogenic quenching can further increase the tensile properties. Oxide bifilms, porosities, low surface quality, and continuous brittle secondary phases surrounding spheroidal particles reduce the mechanical properties.