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采用Gleeble-1500D热模拟试验机对30%SiCp/Al复合材料进行热模拟试验,其变形温度为623~773K、应变速率为0.01~10s-1。采用加工硬化率法对应力-应变数据进行处理,结合lnθ-ε曲线的拐点和(-(lnθ)/ε)-ε)曲线最小值的判据,研究了该复合材料动态再结晶临界条件。结果表明,30%SiCp/2024Al复合材料的真应力-应变曲线主要以动态再结晶软化机制为特征,峰值应力(σp)随变形温度降低或应变速率升高而增加;该材料的lnθ-ε曲线出现拐点,(-(lnθ)/ε)-ε)曲线出现最小值;临界应变(εc)随变形温度升高与应变速率降低而减小,且临界应变与峰值应变(εp)之间具有相关性,即εc=0.563εp;临界应变与Zener-Hollomon参数(Z)之间的函数关系为εc=7.96×10-3Z0.038。
The thermal simulations of 30% SiCp / Al composites were carried out with Gleeble-1500D thermal simulator. The deformation temperature was 623 ~ 773K and the strain rate was 0.01 ~ 10s-1. The stress-strain data were processed by work-hardening method. According to the inflection point of lnθ-ε curve and the criterion of (- (lnθ) / ε) -ε curve, the dynamic recrystallization threshold condition. The results show that the true stress-strain curves of 30% SiCp / 2024Al composites are mainly characterized by the dynamic recrystallization softening mechanism, and the peak stress (σp) increases with decreasing deformation temperature or increasing strain rate. The lnθ-ε curve (- (lnθ) / ε) -ε) curve appears the minimum; the critical strain (εc) decreases with the increase of deformation temperature and the decrease of strain rate, and between the critical strain and peak strain (εp) Εc = 0.563εp; and the critical strain as a function of Zener-Hollomon parameter (Z) is εc = 7.96 × 10-3Z0.038.