Al2O3,TiB2粒子增强铝基复合材料的动态压缩性能和高温蠕变性能

对ＴｉＯ２－Ａｌ－Ｂ和ＴｉＯ２－Ａｌ－Ｂ２Ｏ３体系制备的两种Ａｌ２Ｏ３和ＴｉＢ２原位粒子增强铝基复合材料进行了动态压缩试验和高温拉伸蠕变试验。动态压缩试验表明，随着应变速率的提高，复合材料的强度和初始加工硬化率明显增加。然而，复合材料中含有的条状Ａｌ３Ｔｉ对复合材料的动态机械响应基本没有影响。透射电镜观察表明，在高应变速率下两种复合材料强度和初始加工硬化率的明显提高可由复合材料基体中位错密度的显著

DYNAMIC COMPRESSIONANDHIGH-TEMPERATURE CREEP PROPERTIES OF Al 2O 3 AND TiB 2 IN SITU PARTIC- ULATES REINFORCED ALUMINUM MATRIX COMPOSITES

Dynamic compressive and tensile creep tests were carried out on two Al 2O 3 and TiB 2 in situ particulates reinforced aluminum composites fabricated from TiO 2-Al-B and TiO 2-Al-B 2O 3 systems. The dynamic compressive tests indicated that the strength and initial strain hardening rate of the composites increase considerably with increasing strain rate.However, the strip-like Al 3Ti existing in composite basically had no effect on the dynamic mechanical response of the composites. TEM observations indicated that the obvious increase in the strength and initial strain hardening rate of the two composites could be explained by the significant increase in dislocation density of the composite matrix. Tensile creep tests indicated that the two composites exhibit high values of apparent stress exponent and creep activation energy. The Al 3Ti existing in the composite basically had no effect on the stress dependence of the creep rate and did not decrease the creep resistance of the composite significantly. However, the Al 3Ti increased the temperature dependence of the creep rate of the composite. After incorporating the threshold stress, the creep data of the two composite can be explained by the microstructure invariant model. The invariance of the microstructure of the composites had been verified by TEM examination.