(1. 山东理工大学 机械工程学院，淄博 255000；
2. 山东大学 材料科学与工程学院，济南 250061)
摘 要: 以AZ31镁合金板材为实验材料，先对其进行限制模压变形，再利用超声喷丸技术进行表面处理，研究限制模压变形和超声喷丸复合工艺对材料表层组织和硬度的影响。结果表明：限制模压变形和超声喷丸具有叠加效果，该复合工艺相对于单一工艺能进一步减小AZ31镁合金的晶粒尺寸，增强表面硬度。经复合工艺处理后，AZ31镁合金的最小平均晶粒尺寸为7.52 μm，相比于原始试样细化43.16%；表面硬度最高达到236 HV，相比于原始试样提高306.90%。此外，与限制模压变形相比，超声喷丸对AZ31镁合金表层组织和硬度的影响更加明显。其中，随着喷丸时间的增加，晶粒逐渐细化，硬度不断升高，但当处理时间达到400 s时，晶粒尺寸不再有明显减小，硬度达到一定极限不再变化。
关键字: AZ31镁合金；限制模压变形；超声喷丸；晶粒细化；硬度提高
（1. School of Mechanical Engineering, Shandong University of Technology, Zibo 255000, China;
2. School of Materials Science and Engineering, Shandong University, Jinan 250061, China）
Abstract:The effects of a composite process of constrained groove pressing (CGP) and ultrasonic shot peening (USP) on the surface microstructures and hardness of AZ31 magnesium alloy were studied. The results show that the superposition effect of CGP and USP can further reduce the grain size of AZ31 magnesium alloy and enhance the surface hardness compared with the single process. After the composite processing, the minimum average grain size of AZ31 magnesium alloy is 7.52 μm, which is 43.16% finer than that of the original sample, and the surface hardness is up to 236 HV, which is 306.90% higher than that of the original sample. In addition, the effect of USP on the surface microstructure and hardness of AZ31 magnesium alloy is more obvious than that of CGP. With the increase of USP treating time, the grains become finer and the hardness becomes higher continuously. However, when the treating time reaches 400 s, the grain size is no longer significantly reduced and the hardness reaches a certain limit.
Key words: AZ31 magnesium alloy; constrained groove pressing; ultrasonic shot peening; grain refinement; hardness increase
