摘要
通过等温压缩实验,研究Al/Cu双金属复合材料在400~500℃、应变速率0.001~0.1 s^(-1)条件下的热变形行为,并考虑复合材料成分体积分数(Al含量为30%~51%)的影响。采用Arrhenius模型和混合定律(ROM)模型建立新的本构方程。流变应力(FS)实验表明,工艺参数和体积分数对复合材料的流变行为有影响,而Cu的体积分数对复合材料的高温流变行为影响更大。对于体积分数为51%、42%和30%Al的复合材料,建立的Arrhenius型本构方程和ROM模型的相关系数(R)分别为0.9826、0.9742和0.9718,其平均相对误差分别为0.18%、1.69%和-0.84%。结果表明,新建立的本构模型能较好地预测双金属复合材料的热加工行为。最后,研究不同工艺条件下复合材料的显微组织,确定三种不同成分Al/Cu复合材料在不同温度、应变和应变速率范围内的主要热变形机制。
The hot deformation behavior of Al/Cu bimetal composites was investigated using isothermal compression tests at temperatures of 400-500℃ and strain rates of 0.001-0.1 s^(-1) by considering the effects of volume fractions of composite components(30%-51%Al).In this regard,new proper constitutive equations were developed using Arrhenius-type and the rule of mixture(ROM)models.Experimental flow stress(FS)showed that processing parameters and volume fraction affect the flow behavior of composite as the volume fraction of copper has a more substantial impact on the flow behavior of the composite rods at elevated temperatures.The values of correlation coefficient(r)and average relative error of the developed Arrhenius-type constitutive equation and ROM model were 0.9826,0.9742 and 0.9718,and also 0.18%,1.69% and -0.84% for volume fractions of 51%,42% and 30%Al,respectively.The results indicate that the newly developed constitutive model can successfully predict the hot working behavior of the considered bimetal composite.Finally,the microstructure of composites was investigated under different processing conditions.The dominant mechanisms for three considered volume fractions were identified at different temperatures,strains,and strain rates specified for the hot deformation of the Al/Cu composite.
