YT01低能量多碰塑性变形研究

为研究碰撞能对金属材料多碰塑性变形的影响,在实验室用自制的凸轮机械式多碰试验机对YT01试样进行了低能量多碰试验,采用坐标网格法、SEM、金相显微镜等方法研究了不同碰撞能对试样的塑性变形率、显微组织结构的影响.实验结果表明:峰值冲击应力不变时,多冲碰撞能量越大,试样累积塑性变形量也越大;随着碰撞次数的增加,试样塑性变形率减小并趋于平缓,塑性变形终止于距冲击表面69 mm处;256 000次碰撞后,试样显微组织细化,晶粒界增多.金属材料多冲碰撞塑性变形不仅与峰值冲击碰撞应力有关,也与冲击碰撞能有关.

Plastic deformation of YT01 submitted to repeated low-energy impacts

To evaluate the effect of impact energy on plastic deformation of metal, repeated impact tests of YT01 were performed on the cam mechanical multi touch machine in the laboratory. The plastic deformation of YT01 was investigated by Coordinate Grid method, while the microstructure and phase were investigated by scanning electron microscope (SEM) and metalloscope in order to understand the different impact energy on the plastic deformation and microstructure. The results show that: the cumulative plastic deformation was greater with increasing impact energy and unchanged impact stress. The plastic deformation rate decreased with the increase of the impact number. The plastic deformation stopped at 6-9 mm from the top surface. After 256 000 repeated impacts, microstructure refinement and increased grain boundaries occurred. Meanwhile, transgranular cracks and holes were presented at 6-9 mm from the contact surface due to intense shear deformation in the sample. As a consequence, the plastic deformation of metallic material is not only related with impact stress but also with impact energy.