摘要
采用HK30C金属表面加工控制设备对精车加工后的AZ31B镁合金试棒进行超声表面滚压处理,并设置不同的滚压量进行对比。经过超声滚压处理后,试样表面粗糙度最低可降至0.1009μm,相较于精车试样(Ra=1.2326μm)下降了91.8%。随着滚压量增大,试样表层平均晶粒尺寸逐渐减小,晶粒细化层深度逐渐增大,平均晶粒尺寸相较于心部下降98%以上,晶粒细化层深度最大可达270μm,表层显微硬度相较于心部提高了117.14%。超声表面滚压强化后,AZ31B镁合金试样摩擦磨损机制明显改变,摩擦磨损性能得到明显提升。摩擦因数由0.337降为0.279,质量损失由32.44 mg减少到9.07 mg。因而,超声表面滚压导致的表面粗糙度降低、表层晶粒细化以及剧烈的塑性变形是影响AZ31B镁合金表层显微硬度、摩擦磨损性能的主要原因。
AZ31 B Mg alloy samples after finish turning processing were treated by using HK30 C USRP machine,and effects of different rolling rate on microstructure of the AZ31 B alloy were analyzed.The results indicate that the surface roughness of 0.1009μm is decreased by 91.8%compared with the untreated specimen(Ra=1.2326μm).The severe plastic deformation in the surface of AZ31 B is formed by USRP,and the grains in the surfaces layer of AZ31 B are remarkably refined.The microstructure in surface region of the USRPed specimens is presented as nanostructure whose average grain size is decreased by 98%compared with the interior grains,and the depth of the grain refinement in surface layer after USRPed reaches about 270μm.Meanwhile,the surface microhardness is increased by 117.14%compared with the interior ones.The wear resistance of AZ31 B Mg alloy samples is significantly improved after USRP.The friction coefficient is decreased from 0.337 to 0.279.The mass loss is reduced from 32.44 mg to 9.07 mg.The surface roughness reduction,grain refinement and extreme plastic deformation caused by USRP are responsible for promoting the hardness and wear resistance of AZ31 B Mg alloy.
作者
杨细莲
邹宇
黄文婷
黄美红
Yang Xilian;Zou Yu;Huang Wenting;Huang Meihong(School of Mechanical and Electrical Engineering,Jiangxi Agricultural Engineering Vocational College)
出处
《特种铸造及有色合金》
CAS
北大核心
2020年第11期1214-1218,共5页
Special Casting & Nonferrous Alloys
