Study On Size Effect Of ZL101 Aluminum Semi-Solid Alloy With High Solid Fraction

In this paper,the microstructural analysis and semi-solid microupsetting experiments were carried out to study the material properties of ZL101 semi-solid aluminum alloy.The main contents are as follows:1 According to the characteristics of semi-solid forming and microforming of ZL101 alloy,the semi-solid remelting process was designed to study the evolution process and evolution mechanism of high solid fraction semisolid microstructure.It is possible to obtain the microstructure of spherical solid phase surrounded or partly surrounded by liquid phase with different solid fraction by controlling the holding time at the temperature above the eutectic point.The solid phase ratios of 86%,74%,65%,and 60% were obtained at 580 ? for 5 min,10 min,15 min and 20 min,the grain sizes were 110 m,121 m,124 m and 128 m,respectively.2 In order to overcome the difficulty of temperature control and transfer of micro-semi-solid sample,the semi-solid micro-upsetting mold of ZL101 alloy has been designed and realize.The experimental results show that the mold can be used in semi-solid remelting and micro-upsetting.3 The effects of holding temperature,holding time and specimen size on the flow stress curve of ZL101 semi-solid alloy were analyzed.The effect of scale effect on the microstructure of ZL101 alloy was investigated in semi-solid micro-upsetting experiment.The existence conditions were analyzed.4 Based on the experimental data of isothermal upsetting of ZL101 alloy and semi-solid micro-macro scale model,the external dimensions and grain size were introduced into a new model.The constitutive model of ZL101 alloy with high solid fraction was obtained by using genetic algorithm.The maximum error of stress is 5.7% between the calculated results and the experimental flow curves.