δ-Al_2O_3短纤维增强Al合金复合材料热残余应力及其影响

Thermal Residual Stresses and Their Effects on Properties of δ-Al_2O_3 Short Fiber Reinforced Al Alloy Composites

用弹塑性有限元法和双纤维模型研究了δAl2O3 短纤维增强Al合金复合材料在室温下的热残余应力的分布及其对复合材料整体力学性能的影响.计算了体积分数为20%的3种δAl2O3 /Al合金复合材料的拉伸应力应变关系,并与实验结果比较.纤维间相互作用使复合材料基体中的热残余应力的大小发生了变化,但对其空间分布规律没有影响.对于体积分数为20%的短纤维增强δAl2O3 /Al 5. 5Mg和δAl2O3 /Al 5. 5Zn复合材料,用双纤维模型的三维弹塑性有限元方法计算的应力应变曲线与实验曲线符合得较好,但δAl2O3 /Al 12Si复合材料的模拟结果与实验结果相比误差较大.

A double fiber model was proposed. The distribution of thermal residual stresses in δ-Al2O3f/A1 alloy composites and the effects of thermal residual stresses on the properties of the composites were calculated with a double fiber model and elasto-plastic finite element method. Tensile stress-strain curves of three δ-Al2O3/ Al alloy composites were obtained with the effect of thermal residual stresses taken into account and compared with the experimental results. The effects between neighboring fibers result in the changes in magnitude of thermal residual stresses, but have no influence on their space distribution. Reasonable consistency was achieved between the simulated and experimental stress-strain curves for δ-Al2O3/Al-5.5 Mg and δ-Al2O3/Al-5.5 Zn composites, but there was significant error in the simulated curves compared with the experimental results for δ-Al2O3/ Al-12 Si composite.