Hot Deformation Behavior and Processing Map of SiCp/2024Al Composite

摘要:

采用Gleeble-1500D热模拟试验机，对30%SiCp/2024A1复合材料在温度为350～500 ℃、应变速率为0.01～10 s-1条件下进行热压缩试验，研究该复合材料的热变形行为与热加工特征，建立热变形本构方程和加工图。结果表明，30%SiCp/2024A1复合材料的流变应力随温度升高而降低，随应变速率增大而升高，说明该复合材料是一个正应变速率敏感的材料，其热压缩变形时的流变应力可采用Zener-Hollomon参数的双曲正弦形式来描述，在本实验条件下平均热变形激活能Q为153.251 kJ/mol。为了证实其潜在的可加工性，对加工图中的稳定区和失稳区进行标识，并通过微观组织得到验证。综合考虑热加工图和显微结构，变形温度为450 ℃，应变速率为 1 s-1是复合材料适宜的热变形条件。

Abstract:

The hot deformation behavior of 30%SiCp/2024 aluminum alloy composites was studied by hot compression tests using Gleeble-1500D thermo-mechanical simulator at the temperatures ranging from 350~500 ℃ under strain rates of 0.01~10 s-1. The true stress-true strain curves were obtained in the tests. Constitutive equation and processing map were established. The results show that the flow stress decreases with the increase of deformation temperature at a constant strain rate, and increases with the increase of strain rate at constant temperature, indicating that composite is a positive strain rate sensitive material. The flow stress behavior of composite during hot compression deformation can be represented by a Zener-Hollomon parameter in the hyperbolic sine form. Its activation energy for hot deformation Q is 153.251 kJ/mol. To demonstrate the potential workability, the stable zones and the instability zones in processing map were identified and verified through micrographs. Considering processing map and microstructure, the hot deformation should be carried out at the temperature of 450 ℃ and the strain rate of 1 s-1.