强流脉冲电子束处理对GW103K镁合金表面微观结构和性能的影响

Effect of High Current Pulsed Electron Beam Treatment on Surface Microstructure and Properties of GW103K Magnesium Alloy

采用强流脉冲电子束(HCPEB)对GW103K镁合金进行表面处理,研究了不同脉冲次数(5次,15次)处理后合金的表面微观结构、硬度和耐腐蚀性能。结果表明:经HCPEB处理后,GW103K镁合金表面存在大量火山坑、收缩针孔和孪晶,原始组织中的β-Mg5(Gd,Y)颗粒基本溶解在基体中;15次脉冲HCPEB处理后合金的表面形貌和化学成分比5次脉冲HCPEB处理后的更均匀;随着HCPEB脉冲次数由5次增加到15次,合金表面重熔层的厚度由约7.67μm增加到约13.70μm;HCPEB处理后距表面50~250μm处的显微硬度均高于基体的,且均在距表面约70μm处达到最大;在质量分数3.5%NaCl溶液中,经5次脉冲HCPEB处理后合金的自腐蚀电流密度最小,耐腐蚀性能最好,这与钆、钇的溶解以及表面残余压应力有关。

The surface treatment of GW103 K magnesium alloy was carried out by high current pulsed electron beam(HCPEB).The surface microstructure,hardness and corrosion resistance of the alloy after HCPEB treatment with different pulses(5,15 pulses)were investigated.The results show that after HCPEB treatment,the surface of GW103 K magnesium alloy had a large number of craters,pinholes and twins,and theβ-Mg5(Gd,Y)phase observed in original structure was dissolved in the matrix.The surface morphology and chemical composition of the alloy after 15-pulse HCPEB treatment were more uniform than those after 5-pulse HCPEB treatment.As the HCPEB pulses increased from 5 to 15,the thickness of the remelted layer on the alloy surface increased from about7.67μm to about 13.70μm.After HCPEB treatment,the values at a distance of 50μm to 250μm from the surface was higher than that of the matrix,and reached the maximum values at a distance of about 70μm from the surface.In the 3.5 wt%NaCl solution,the free-corrosion current density of the alloy after 5-pulse HCPEB treatment was the smallest and the corrosion resistance was the best,ascribing to the dissolution of thorium and yttrium and the surface residual compressive stress.