超声表面滚压工艺对固溶态ZK60镁合金硬度梯度及显微组织的影响

Effect of Ultrasonic Surface Rolling Process on Hardness Gradientand Microstructure of Solid Solution ZK60 Magnesium Alloy

采用超声表面滚压工艺,通过粗糙度测试、显微组织观察、硬度测试等方法,研究了不同滚压静压力和滚压道次对固溶态ZK60镁合金硬度梯度及显微组织的影响。结果表明:固溶态ZK60镁合金材料通过超声滚压后,样品获得了显微梯度组织和对应的梯度硬度变化;随着超声滚压的静压力(150、250、350 N)和滚压道次(6、9、12、15和18)的不断增大,样品的表层显微硬度值与梯度强化层深度也随之增大,表层的晶粒得到一定程度的细化;同时,表层显微组织形成的流变层更加明显,样品的表面完整性更好,样品的粗造度值最小为Ra=0.135μm,表层硬度值最大为130 HV。

The ultrasonic surface rolling processing(USRP)was adopted,and the effects of different rolling static pressure and rolling passes on the hardness gradient and microstructure of solid solution ZK60 magnesium alloy were studied by roughness test,micro-structure observation and hardness test.The results show that,the micro-gradient structure and the corresponding gradient hardness changes of the solid solution ZK60 magnesium alloy are obtained after ultrasonic rolling.With the increase of static pressure(150 N,250 N and 350 N)and rolling passes(6,9,12,15 and 18)of ultrasonic rolling,the surface microhardness and the depth of gradient strengthened layer of the samples also increase,and the surface grains are refined to a certain extent.Meanwhile,the rheological layer formed on the surface micro-structure is more obvious,and the surface integrity of the sample is better.The minimum roughness of the sample is Ra=0.135μm,and the maximum surface hardness is 130 HV.