Constitutive model and microstructure evolution of thermal deformation behavior of in situ TiB2p/Al-Zn-Mg-Cu composites with high Zn content

The deformation behavior of in situ TiB2 particle reinforced Al-Zn-Mg-Cu matrix composites with high Zn content was investigated through thermal compression tests. A comparative analysis of several constitutive models was performed, including the phenomenological modified Johnson-Cook (JC) and strain-compensated Arrhenius-type models, as well as the physically based modified and optimized Zerilli-Armstrong (ZA) models. In contrast to other materials, it is found that the accuracy of the modified JC and ZA models is significantly affected by the reference strain rate. When this was factored in, the optimized ZA model demonstrated superior accuracy, with a correlation coefficient (R) of 0.9986 and an average absolute relative error (AARE) of 2.15 %, while requiring the fewest calculation efforts amongst all of the models attempted. The mechanisms of the microstructural evolution in the composites after thermal deformation were also investigated. This work advances the understanding of TiB2p/Al-Zn-Mg-Cu composites and introduces an improved modeling framework, which is expected to benefit future material design and performance.