铝硅合金表面激光熔凝及等离子体电解氧化制备的复合防护层的组织及热防护性能  

Microstructure and thermal protective properties of composite protective layer prepared on surface of aluminum-silicon alloy by laser melting and plasma electrolytic oxidation

作　　者：焦尚意 王萍[1] 张春青[2] 马群[3] JIAO Shang-yi;WANG Ping;ZHANG Chun-qing;MA Qun(School of Materials and Chemical Engineering,Xi’an Technological University,Xi’an 710021,China;Mechanical Department,Chengde Petroleum College,Chengde 067000,China;Military Academy,Xi’an Technological University,Xi’an 710021,China)

机构地区：[1]西安工业大学材料与化工学院,陕西西安710021 [2]承德石油高等专科学校机械系,河北承德067000 [3]西安工业大学兵研院,陕西西安710021

出　　处：《材料热处理学报》2020年第11期143-152,共10页Transactions of Materials and Heat Treatment

基　　金：陕西高校“金属腐蚀防护与表面工程技术”青年创新团队;陕西省重点研发计划项目(2018GY-111);陕西省教育厅产业化培育项目(17JF009);榆林科技计划项目(2018-2-30)。

摘　　要：采用激光熔凝改性的方法在铝硅合金表面制备了具有一定深度的熔凝层,并在此基础上制备了激光熔凝-等离子体电解氧化(PEO)复合防护层。通过光学显微镜、扫描电镜对激光熔凝改性层组织及PEO膜层组织结构进行分析,采用隔热装置及热冲击性能测试设备分别测试了防护层的热防护性及热冲击性能进行。结果表明,经过激光表面重熔,Al-12Si合金表层形成了以尺寸为3~5μm的等轴晶为主的激光熔凝区、以树枝晶为主的热影响区和以部分未完全熔化相及元素的富集现象为主的临界过渡区3个区域。制备的激光熔凝-PEO复合防护层致密均匀,放电微孔增多且分布均匀,孔隙率由6.83%降低至3.95%,有利于热量的储存隔绝,相比于单纯的PEO膜层,激光熔凝-PEO复合防护层隔热温度由25℃提高至36℃,隔热性能提升了44%,其热冲击性能也显著提升。A melting layer with a certain depth was prepared on the surface of Al-Si alloy by laser melting modification, and a laser melting-plasma electrolytic oxidation(PEO) composite protective layer was prepared. Microstructure of laser remelting modified layer and PEO layer was analyzed by means of optical microscope and scanning electron microscopy, and the thermal protective performance and thermal shock performance of the protective layer were tested by means of thermal insulation device and thermal shock test equipment. The result shows that after laser surface remelting, there are three areas on the surface of the Al-12 Si alloy: the remelting area with 3-5 μm equiaxed crystal as the dominated, the heat affected area with dendrite as the dominated and the critical transition area with partial incomplete melting phase and element enrichment as the dominated. The prepared laser remelting-PEO composite protective layer is dense and uniform, the discharge micropores increase and the distribution is uniform, and the porosity decreases from 6.83% to 3.95%, which is beneficial to heat storage isolation. Compared with the single PEO layer, the thermal insulation temperature of the laser remelting-PEO composite protective layer is increased from 25 ℃ to 36 ℃, the thermal insulation performance is improved by 44%, and the thermal shock performance is also significantly improved.

关 键 词：AL-SI合金 激光熔凝 等离子体电解氧化 热防护性能 

分 类 号：TG174.44[金属学及工艺—金属表面处理]