喷丸致材料晶粒细化的实验研究

Experimental Investigation on Grain Refinement of Copper due to Shot Peening

喷丸是通过剧烈塑性变形使材料细化同时硬度得以提高的方法之一。用纯铜作为实验材料在高能气动喷丸实验机上进行实验，利用显微硬度仪以及电子背散射衍射方法对经喷丸处理的试样进行硬度及晶粒尺寸测量。结果表明：当处理时间为1333．3S时，平均晶粒尺寸由原始的25．48μm细化至2．52μm，且显微硬度由原来的0．58GPa增加到1．25GPa。实验结果验证了该方法的有效性。

SP is a typical severe plastic deformation method not only to produce ultra - fine grains of metallic materials, but also to increase the hardness. An experimental investigation was carried out on pure copper specimens by means of a shot peening machine driven by high energy air pressure. A micro -hardness indenter, an optical microscope and a scanning electron microscope equipped with electrical back scatter diffraction apparatus were also utilized in this experimental investigation. The results show that the mean grain size in the specimens with 1 333.3 s is 2.52 microns compared with the original value of 25.48 microns. The micro - hardness testing on the specimens shows the hardness increased from O. 58GPa to 1.25 GPa after SP treatment.