La变质对亚共晶Al-xMg_(2)Si组织及磨损性能的影响

Effects of La Modification on Structure and Wear Properties of Hypoeutectic Al-xMg_(2)Si

通过摩擦磨损试验研究了经0.4%的La处理的不同Mg_(2)Si含量的亚共晶Al-xMg_(2)Si合金的组织和磨损性能。结果表明,经0.4%的La变质后,合金磨损速率均降低,且磨损速率平稳波动较小;未变质时,合金的磨损机制为疲劳磨损+磨粒磨损+粘着磨损,变质后以粘着磨损为主,伴有氧化磨损+轻微磨粒磨损。由纵截面显微组织和硬度可知,随着硬化层厚度增加,合金的耐磨性增加,经0.4%的La变质后合金硬化层厚度增加,表现出较好的耐磨性,且变质对Al-10Mg_(2)Si和Al-11Mg_(2)Si合金的耐磨性提高更明显,使磨损速率降低,表现出较好的耐磨性和综合力学性能。

Friction-wear test was carried out to investigate the effect of 0.4%La modification on microstructure and wear properties of hypoeutectic Al-xMg_(2)Si with different Mg_(2)Si contents.The results indicate that after 0.4%La modification,the wear rate is decreased,which fluctuates stably and slightly.The wear mechanism is characterized by fatigue wear+abrasive wear+adhesive wear before modification,which is dominated by adhesive wear after modification,accompanied with oxidation wear and slight abrasive wear.The microstructure and hardness of longitudinal section reveal that the wear resistance is increased with the increase of hardened layer thickness.After 0.4%La modification,the thickness of hardened layer is increased,exhibiting desirable wear resistance.Moreover,the modification has a more significant effect on the wear resistance of Al-10Mg_(2)Si and Al-11Mg_(2)Si,reducing the wear rate and leading to desirable wear resistance and comprehensive mechanical properties.