316L不锈钢强流脉冲电子束表面改性研究Ⅰ.表面选择净化及机理

在强流脉冲电子束作用下,316L不锈钢表面因MnS夹杂或界面过热喷发而形成火山坑,MnS夹杂物是轰击过程中形成火山坑的核心.随着轰击次数的增加,表层中MnS夹杂物随喷发而逐渐减少,实现了材料的表面选择净化.与此同时,在反复轰击过程中,火山坑的密度随轰击次数减少,火山坑形态逐渐由心部有孔转变为心部无孔,表面缺陷得以修复.

SURFACE MODIFICATION OF 316L STAINLESS STEEL BY HIGH CURRENT PULSED ELECTRON BEAM Part I Selective surface purification and its mechanism

In this paper, the processing and corresponding mechanisms of the surface modification of 316L stainless steel by high current pulsed electron beam were studied in detail. The results showed that MnS inclusions in the 316LSS served as the nucleation sites for craters formed during the bombardment. The overheating of these inclusions or their interfaces and following eruptions are believed to be the reason for the crater formations. As a result, MnS inclusions in the surface layer decreased with the increasing number of pulses, leading to a selective surface purification of the material. On the other hand, the physical damages induced by the electron beam bombardment are repaired after repeated pulses, that is, the crater density decreases with the increasing number of bombardments, meanwhile the holes in the crater centers are removed gradually.