SiC_p/Al-2618复合材料的应力-应变曲线和增强颗粒受力的模拟

SIMULATION OF STRESS IN REINFORCEMENTS AND STRESS-STRAIN CURVE OF SiC_p/Al-2618 MATRIX COMPOSITE

对体积分数为15%的SiC颗粒增强Al-2618复合材料,采用不同的热处理条件得到硬基体和软基体两种不同性能的合金.建立了一个基于Eshelby等效夹杂方法的颗粒复合体力学模型,通过引入基体割线模量和切线模量的方法模拟了上述两种复合材料的应力-应变曲线,计算增强粒子的受力情况.采用基于单胞模型的有限元方法,利用ANSYS商品软件进行了同样的模拟工作并进行对比.通过与实验曲线的对照表明,Eshelby颗粒复合体力学模型可以更准确的预测出硬基体和软基体两种复合材料的应力-应变曲线,而有限元单胞模型不适用于预测软基体复合材料.预测出的粒子中的受力远高于基体中的受力,表明载荷传递是颗粒增强金属基复合材料强度提高的主要机理.

A 15% （volume fraction） SiC particle-reinforced A1-2618 matrix composite was selected to simula;e its stress-strain curve and the stress in the reinforcing particles. The simulation was also carried out to two composites with hard matrix （T6 treatment） and soft matrix （T4 treatment）. An analytical model was established based on Eshelby equivalent inclusion approach to do the simulation by introducing numerical secant moduli and tangent moduli scheme, respectively. The same modeling work was carried out by FEM analysis based on the unit cell model using a commercial ANSYS code. Through the comparison of the results between the simulation and experimental results, it is shown that the Eshelby model can predict the stress-strain curve of the composite with both hard matrix and soft matrix by introducing different numerical moduli, while the FEM model can not be used to simulate the stress-strain curve of composite with soft matrix. The stress in the particles is much higher than that in matrix shown by the simulation, which indicates that load transfer is the main strengthening mechanism for the particle-reinforced metal matrix composite.