退火处理等径角挤压7090/SiCp复合材料的显微组织与断裂行为

Mechanical Properties and Fracture Behavior of ECAP 7090/SiCp Composite after Annealing Treatment

采用喷射沉积工艺制备了SiCp/Al-Zn-Mg-Cu超高强铝合金基复合材料,通过等径角挤压工艺对挤压后的复合材料试样进行了大塑性变形。研究了不同退火处理制度对等径角挤压试样室温力学性能及显微组织的影响,观察了不同状态的断裂特征,结果表明,退火处理后,等径角挤压试样发生韧性断裂,断口出现大量的韧窝,韧窝底部存在一定量等径角剪切破碎产生的细小SiC粒子。同时该复合材料等径角挤压后的力学性能及断裂行为与退火处理制度有关,随着退火温度的升高,复合材料的室温拉伸强度逐渐增大,但其塑性逐渐降低。SiC增强颗粒与Al合金基体之间的界面结合力较小,在拉伸过程中以拔出的形式为主。

SiCp/Al-Zn-Mg-Cu composite is prepared by multi-layer spray deposition, and ECAP deformation is carried out for the as-extruded sarnples. The effects of annealing treatment on ambient mechanical properties, microstructures and the fracture features of the ECAPed samples are researched. The results show that the composite occurs toughness fracture, there are many fine SiC particles broken by ECAP at the bottom of the fracture surface. The ambient mechanical properties vary with annealing temperature＇s evolution, the tensile strength increases along with the hoist of annealing temperature, however the elongation decrease gradually. The combining strength between SiC particles and Al matrix alloy is feeblish and the SiC particles mainly are drawing out.