退火处理对SiC_w/Al复合材料应力腐蚀开裂行为的影响

EFFECT OF ANNEALING TREATMENT ON STRESS CORROSION CRACKING BEHAVIOR OF SiC WHISKER REINFORCED ALUMINUM COMPOSITE

采用双悬臂梁试验方法， 研究了不同温度的退火处理对纯铝基复合材料及ＬＹ１２ 铝基复合材料应力腐蚀开裂行为的影响。应力测试及透射电镜观察结果表明， 不同温度的退火处理通过松弛复合材料的残余应力及改变基体的位错组态改善了复合材料的应力腐蚀性能。随退火温度的升高， 两种复合材料的应力腐蚀裂纹稳态扩展速率降低； 临界应力场强度因子ＫＩＳＣＣ增高；

The aluminum matrix composite reinforced by SiC whisker have been extensively studied because of their excellent properties. But little was known about the stress corrosion cracking (SCC) behavior of SiC w/Al composite. In the present research, the effect of annealing treatment on the SCC behavior of SiC w/Al and SiC w/2024 composites was investigated using Double Cantilever Beam (DCB) specimen in 3.5% NaCl solution. The results indicated that annealing treatment improved the SCC behavior of the two composites by relaxing residual stress and changing matrix microstructure. With the increase in annealing temperature, the SCC propagation rate of the two composites decreased and the K ISCC increased. The TEM observation showed that dislocation density in matrix of the composites decreased greatly after annealing treatment. As a result, the sensibility to SCC of the composites was improved.