SiC_p/8%TiB_2混杂增强铝基复合材料高温流变应力行为研究

采用Gleeble-3500热模拟试验机对SiC_p/8%TiB_2铝基复合材料在温度为350, 400, 450, 500℃,应变速率为0.001, 0.01, 0.1, 1 ^s-1条件下进行热压缩试验,探究其高温流变应力行为;建立SiC_p/8%TiB_2铝基复合材料应变速率和流动应力的本构方程,采用正弦双曲Arrhenius方程解释流动应力行为。建立基于动态材料模型(DMM)的热加工图来解释SiC_p/8%TiB_2铝基复合材料的热加工性,利用扫描电镜进行微观组织分析,以验证热加工图的可靠性。研究结果表明:SiC_p/8%TiB_2铝基复合材料的变形活化能为263.967kJ/mol,最佳变形温度为490～500℃,应变速率为0.001～0.030s^-1,此时功率耗散系数达到峰值为23%。

High Temperature Flow Stress Behavior of SiC_p/8% TiB_2 Hybrid Reinforced Aluminum Matrix Composites

The hot compression test of SiCp/8%TiB2 aluminum matrix composites was performed by using thermal simulation tests in a Gleeble-3500 simulator.The thermal compression was tested at temperature of 350,400,450,500 ℃ and strain rate of 0.001,0.01,0.1,1 s^-1 to investigate the behavior of high temperature flow stress.The constitutive equations of strain rate and flow stress of SiCp/8%TiB2 aluminum matrix composites were established,and the sinusoidal hyperbolic Arrhenius equation was used to explain the flow stress behavior.A processing diagram based on dynamic material model (DMM) was established to explain the hot workability of SiCp/8%TiB2 aluminum matrix composites.The microstructure analysis was carried out by scanning electron microscopy to verify the reliability of the hot processed image.The results showed that the deformation activation energy was 263.967 kJ/mol,the optimum processing conditions for the SiCp/8%TiB2 aluminum matrix composites were at the deformation temperature range of 490~500 ℃ and the strain rate range of 0.001~0.030 s^-1 with the power dissipation efficiency reached the peak of 23%.