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采用真空压力浸渗法制备了短切碳纤维体积分数为15%的AZ91D镁基复合材料(C_sf/AZ91D),通过等温恒应变率压缩试验,研究了复合材料在变形温度为400~460℃、应变速率为0.001~0.1s~(-1)、最大真应变为0.7条件下的流变应力和动态再结晶行为。结果表明,复合材料流变应力曲线呈现显著的动态再结晶软化特征,动态再结晶临界应变随变形温度升高或应变速率降低而减小,其与Z参数之间的函数关系为εc=1.6×10~(-3) Z~(0.037 2);动态再结晶临界应变和峰值应变之间的关系为ε_c=0.385 2ε_p;同等变形条件下,复合材料动态再结晶的临界应变远小于AZ91D镁合金,短切碳纤维促进了基体镁合金动态再结晶发生,同时细化了其再结晶晶粒。
The AZ91D magnesium matrix composites (C_sf / AZ91D) with 15% volume fraction of chopped carbon fibers were prepared by vacuum infiltration method. The compressive strength of AZ91D magnesium matrix composites (C_sf / AZ91D) The flow stress and dynamic recrystallization behavior at the rate of 0.001 ~ 0.1s ~ (-1) and maximum true strain of 0.7. The results show that the flow stress-strain curves of composites show significant dynamic recrystallization-softening characteristics. The critical dynamic strain recrystallization strain decreases with the increase of deformation temperature or strain rate. The relationship between the critical strain and the Z-parameter is εc = 1.6 × 10 ~ (-3) Z ~ (0.037 2). The relationship between dynamic recrystallization critical strain and peak strain is ε_c = 0.385 2ε_p. Under the same deformation conditions, the critical strain of dynamic recrystallization of composite is much smaller than that of AZ91D magnesium alloy, Chopped carbon fiber promoted the dynamic recrystallization of matrix magnesium alloy and refined the recrystallized grains.