机构地区: 中国科学院固体物理研究所合肥物质科学研究院固体物理研究所
出 处: 《金属学报》 1996年第5期510-515,共6页
摘 要: 系统地研究了[110]与[100]两种特殊晶轴取向的高纯铝单晶在1×10(-4)-6×10(-4)室温拉压疲劳应变振幅条件下的应力σm、内耗Q(-1)和加载最大处超声衰减△αt,的循环响应行为,对疲劳不同阶段的位错组态作了详细的TEM观察。结果表明:两种单晶的循环应力均显示出“硬化-软化-二次硬化”的三个阶段特征。内耗的变化和应力进程同步,但趋势相反.超声衰减开始随圈数增大,达到一极大值后减小。这三种参数的变化是由位错与位错的相互作用机制控制。 Push-pull fatigue deformation of [110] and [100] Al-single crystals was performed at room temperature at strain amplitudes in the range (1 to 6) × 10 ̄(-4). Variation of the stress σ, internal friction Q ̄(-1), and ultrasonic attenuation △α vs cycle number N under various strain amplitudes were measured systematically, and the relative dislocation configuration at different stages of fatigue was observed by TEM. The results indicate that the σ-N curve goes through a hardening -softening-secondary hardening sequence during push-pull fatigue in the two kinds of Al-single crystals. The change in the internal friction vs cycle N is synchronous and reverse with that of the stress. The ultrasonic attenuation △α increases with N at the beginning, after reaching a hump, decreases gradually. The variation of this three parameter is controled by the mechanism of interaction between dislocation segments.