强流脉冲电子束对50BA钢显微形貌的影响

Effects of High Current Pulsed Electron Beam on Microscopic Morphology of 50BA Steel

采用不同脉冲次数的强流脉冲电子束（HCPEB）对50BA钢表面进行轰击处理,观察处理前后的试样形貌变化。结果表明：经强流脉冲电子束处理后,试样表面出现弥散分布“熔坑”和相变组织的改性层;随着脉冲次数的增加,熔坑尺寸先增大后变小,熔坑数量逐渐减少,熔坑深度逐渐变浅,试样表面逐渐趋于平滑,改性层的厚度逐渐增厚;相变产生的马氏体含量相对减少而残余奥氏体含量相对增加;快速凝固使试样表面层的晶粒细化,分布更为均匀。

The ionic bombardment on 50BA steel surface was carried out by different pulse numbers of high currentpulsed electron beam （HCPEB）, and the changes of surface morphology of the samples before and after treatment wereobserved. The results show that after high current pulsed electron beam treatment, the sample surface generates dispersed＂crater＂ and modified layer of phase change microstructure. With the increase of the numbers of pulses, the size of craterincreases firsty and then becomes small. The number of craters gradually reduces and the depth gradually becomes shallow,the surface of the sample gradually tends to be smooth, and the thickness of the modified layer increases gradually. Thecontent of martensite produced by phase transformation relatively reduces while the content of retained austenite relativelyincreases. The rapid solidification makes the sample surface grain refine and the grains distribute more uniform.