Morphology observation and analysis of hard phase of 2219 aluminum alloy with multi-directional upsetting and stretching
To further optimize the mechanical properties of 2219 aluminum alloy,the multi-directional upsetting and stretching process was used to improve the hard phase morphologies of 2219 aluminum alloy.As the cumulative deformation amount increases to 7.9,the ar-ea percentage of hard phase decreases from 9.66%to 7.37%,and the percentage of hard phase with the length-to-diameter ratio greater than 3 decreases from the initial 83.15%to 34.23%.Based on the strain gradient theory,the micro-model of the long elliptical hard phase was established.Considering the scale effect of hard phase,the stress concentration coefficient increases from 3.17 to 11.67 when the length-to-diameter ratio increases from 1 to 8.With the increase of deformation amount,the scale effect of hard phase gradually weak-ens.The multi-directional upsetting and stretching experiment proves that it can improve the hard phase morphologies effectively.By com-paring the experimental results with the calculated results,the feasibility of applying strain gradient theory to hard phase analysis of 2219 aluminum alloy was proved.
2219 aluminum alloymulti-directional upsetting and stretchinghard phasemicromechanics