【摘要】 Portevin-Le Chatelier(PLC)效应作为广泛存在于各种合金材料中的重要塑性失稳现象一直受到研究者的广泛关注。本文对镁原子质量百分含量分别为2.5%和5%的两种铝合金-国标LF2和LF5铝合金进行宏观拉伸实验和透射电子显微镜观察实验。通过宏观和微观实验结果的对比分析表明,由于LF5合金中作为溶质的Mg原子的含量相对于LF2合金成倍增加导致析出相颗粒数量也成倍增加,进而引起PLC效应在强度和加工硬化时间的倍增,这些对应关系表明Al-Mg合金中析出相颗粒是产生并影响PLC效应的重要因素。实验结果显示虽然析出相颗粒数量在多方面影响PLC效应,但是对其飞行时间的影响却微乎其微。更多还原

【Abstract】 The Portevin-Le Chatelier (PLC) effect, as one of the most prominent examples of plastic instabilities, has attracted many researchers’ attention. In this paper, the PLC effect in LF2 alloy (Al-2.5%Mg) and LF5 alloy (Al-5%Mg) is studied by macro tensile test and the micro-structure of these alloys are also investigated by transmission electron microscopy. Comparison between the macro tensile test result and the micro structure of the alloys shows that as the content of Mg increases doubly in LF5 alloy, the amount of the precipitation particles also increases doubly, with causes further increase in the intensity and the hardening time of the PLC effect. These relevant changes prove that the precipitation particles are an important factor resulting in and further influencing the PLC effect. The result also shows that although the amount of the precipitation affect the PLC effect in many ways, it can hardly affect the flying time of the PLC effect.更多还原