FSP法制备细晶镁合金微观组织及其耐腐蚀性能

Microstructure and corrosion resistance of fine-grained magnesium alloy prepared by FSP

采用搅拌摩擦加工(Friction stir processing,FSP)技术对AZ31镁合金进行加工处理,通过金相显微镜(OM)、显微硬度计、电子万能拉伸试验机、扫描电镜(SEM)与浸泡腐蚀等手段,研究了经过FSP加工后镁合金的微观组织、硬度及耐蚀性能。结果表明,改变FSP加工参数可得到不同程度的AZ31镁合金细晶组织,力学性能较母材均有所提升;当旋转速度为750 r/min、加工速度为47. 5 mm·min-1时,镁合金微观组织细化最显著,力学性能最优。FSP加工产生动态再结晶,致使晶界增多,Mg17Al12相发生固溶,使750 r/min-47. 5 mm·min-1参数下的试样在3. 5wt%Na Cl溶液中的耐蚀性能有较大提升。

AZ31 magnesium alloy was processed by friction stir processing(FSP)technology.Microstructure and mechanical properties of the magnesium alloy processed by FSP were studied by means of metallographic microscope,microhardness tester,electronic universal tensile tester,scanning electron microscope,and the corrosion resistance is tested by immersion corrosion.The results show that the fine grained microstructure of AZ31 magnesium alloy can be successfully obtained by applying different FSP parameters,and the mechanical properties are improved compared with that of the base metal.When the rotating speed is 750 r/min and the processing speed is 47.5 mm·min-1,the refinement is significant and the mechanical properties are preferable.During FSP processing,dynamic recrystallization results in the increase of grain boundaries and solid solution of phase Mg17 Al12,which exceedingly improves the corrosion resistance of the specimen prepared by 750 r/min-47.5 mm·min-1 in 3.5 wt%Na Cl solution.