激光表面重熔对AZ31B镁合金耐腐蚀性能的影响

Influence of Laser Surface Remelting on Corrosion Resistance of AZ31B Magnesium Alloy

为了研究激光表面重熔技术对AZ31B镁合金耐腐蚀性能的影响,采用Olympus型光学显微镜、JEM-2100F型透射电子显微镜和D/MAX-2500型XRD分析了AZ31B镁合金母材和不同激光功率处理后熔凝层的显微组织和物相,采用CHI660E型电化学检测系统分析了AZ31B镁合金熔凝层的电化学腐蚀性能。分析结果表明,激光表面重熔处理后,熔凝层晶粒得到显著细化,且随着激光功率的增加而逐渐增加;熔凝层中只有α-Mg和β-Mg_(17)Al_(12)两种物相,并没有形成新相,但β-Mg17Al12析出相的含量增加、尺寸降低,并呈球状均匀分布;激光功率为2 000 W时,在晶粒尺寸和β-Mg17Al12析出相的共同作用下,熔凝层具有最优的耐腐蚀性能。

In order to research the influence of laser surface remelting on corrosion resistance of AZ31 B magnesium alloy,microstructure and phase of magnesium alloy base metal and solidified layer with different laser power treatments were analyzed by Olympus optical microscope, JEM-2100 F transmission electron microscope and D/MAX-2500 XRD, and electrochemical corrosion resistance of AZ31 B magnesium alloy solidified layer was analyzed by CHI660 E electrochemical detecting system. The analysis results showed the grain of fused layers was significantly refined after the laser surface remelting process, and the grain size gradually increased with the increase of laser power; solidified layer only had α-Mg andβ-Mg17 Al12 without any new phases, the content of β-Mg17 Al12 precipitated phase increased, the size reduced, and uniformly distributed with spherical form; when the laser power was 2 000 W, under the joint action of the grain size and β-Mg17 Al12 precipitated phase, the solidified layer had optimum corrosion resistance.