熔体过热处理对亚共晶Al-10Mg2Si合金磨损性能的影响

Effects of Melt Superheating Treatment on Wear Properties of Hypoeutectic Al-10MgSi Alloy

对亚共晶Al-10Mg2Si合金进行熔体过热处理,通过削-盘式摩擦磨损试验研究了显微组织对亚共晶Al-10Mg2Si合金磨损性能的影响。结果表明,熔体过热处理后,初生α-Al相转变为近球状等轴晶,Mg2Si相呈纤维状和短杆状均匀分布,且其二次枝晶间距降低了58%,硬度提高了13.5%,同时其磨损速率降低了16.49%。磨屑由合金未经熔体过热处理的推碾薄片状与卷曲状转变为小块粉末状,剥落区面积减小,剥落坑、犁沟和挤压沟槽均变浅。磨损机制由粘着磨损、氧化磨损和磨粒磨损共存转化为以剥层磨损为主,粘着磨损与部分氧化磨损共存的形式,说明熔体过热处理改善了合金的磨损性能。

The effects of microstructure on the wear properties of hypoeutectic Al-10Mg2Si alloy after melt superheating treatment were investigated by means of the grinding-disk friction and wear test.The results reveal that the primaryα-Al phase is converted from fishbone to equiaxed structure,and Mg2Si phase is uniformly distributed in fibrous and short rod shape after melt superheat treatment.The secondary dendrite interval of Mg2Si phase is decreased by 58%,and the hardness is increased by 13.5%,meanwhile the wear rate is decreased by 16.49%.The wear debris is changed from push milling flake type and curl type without melt superheating treatment to small powder shape.The wear debris are converted from pull-chip and crimp type without superheating treatment to small powder shape.The spalling area is decreased,and the spalling pit,furrow and extrusion groove become shallow.The wear mechanism is dominated from adhesive wear,oxidation wear and abrasive wear to coexisting of delamination wear,adhesive wear and partial oxidation wear,which indicate that the melt superheating process can improve the wear properties of the alloy.