漂珠/AZ91D镁合金复合材料的高温压缩变形行为

High-temperature compression deformation behavior of fly ash cenosphere/AZ91D Mg alloy composites

采用搅拌铸造法制备了漂珠(FAC)/AZ91D镁合金复合材料。研究了该复合材料的高温压缩变形行为,分析了压缩变形温度和应变率对FAC/AZ91D镁合金复合材料压缩变形行为的影响规律,并计算了其热变形激活能。结果表明:FAC/AZ91D镁合金复合材料的高温压缩真应力-真应变曲线分为4个阶段:弹性变形、加工硬化、峰值应力和稳态流变阶段。相同应变率下,FAC/AZ91D镁合金复合材料的峰值应力和稳态流变应力随压缩变形温度的升高而降低;相同压缩变形温度下,流变应力随应变率增大而升高。在相同应变率或相同压缩变形温度下,FAC/AZ91D镁合金复合材料的热变形激活能随压缩应变率或压缩变形温度的升高而增大,其热压缩行为可以用双曲正弦函数形式的Arrhenius关系来描述。压缩变形温度与应变率对FAC/AZ91D镁合金复合材料的高温压缩组织均有重要影响。提高压缩变形温度或增大应变率,均可加速动态再结晶的进程。

Fly ash cenosphere（FAC）/AZ91D Mg alloy composites were prepared using stir casting method. The high-temperature compression deformation behavior of FAC/AZ91D Mg alloy composites was studied, the influ- ences of compression deformation temperature and strain rate on compression deformation behavior of FAC/AZ91D Mg alloy composites were analyzed, and the thermal deformation activation energy was calculated. The results show that the high-temperature compression true stress-true strain curves of FAC/AZ91D Mg alloy composites can be divided into four stages., elastic deformation, work hardening, peak stress and steady-state flow stage. At the same strain rate, the peak stress and steady-state flow stress of FAC/AZ91D Mg alloy composites decrease with increas- ing compression deformation temperaturel at same compression deformation temperature, the flow stress increases with increasing strain rate. At the same strain rate or the same compression deformation temperature, the hot de- formation activation energy of FAC/AZ91D Mg alloy composites increases with the increase of the compression strain rate or the compression deformation temperature. The thermal compression behavior can be described with Arrhenius relationship with hyperbolic sine function form. Both compression deformation temperature and the strain rate have important effects on the high-temperature compression structure of FAC/AZ91D Mg alloy composites. In- creasing the compression deformation temperature or the strain rate can accelerate the process of dynamic recrystalli zation.