激光选区熔化AlSi10Mg表面微弧氧化及其耐磨耐蚀性

摘要

Micro-arc oxidation process was applied to 3D printed parts (material:EOS AlSi 10Mg) after selective laser melting (SLM) to improve its wear resistance and corrosion resistance.The residual stress,microstructure,frictional wear performance and corrosion properties were characterized by X-ray diffraction stress analyzer,SEM,high temperature friction and wear tester,and neutral salt spray tester,respectively.Results show that for the as-built 3D printed specimens,large tensile residual stress (about 200 MPa) is measured on the surface.Meanwhile,the subsequent micro-arc oxidation process promotes the stress release,and thus,numerous micro cracks are observed in the micro arc oxidation layer of the as-built specimens.The surface cracking in the micro-arc oxidation layer is found to be decreased when the as-built specimens are annealed before micro arc oxidation process.Additionally,for the annealed 3D printed specimens after micro arc oxidation treatment,the average frictional coefficient decreased from 0.545 to 0.441 and the anti-corrosion rating increased from 9 to 10.Clearly,the thermal stress in SLM 3D printing process significantly influences the effectiveness of the micro-arc oxidation process.%为了提高轻质合金3D打印的耐磨、耐蚀性能,对激光选区熔化(SLM)铝合金(EOS:AlSi10Mg)打印成形后进行表面微弧氧化.采用应力分析仪、扫描电子显微镜、高温摩擦磨损、中性盐雾试验箱等设备,进行了残余应力测试,微观组织分析,摩擦磨损和腐蚀性能试验.结果表明,3D打印铝合金试样直接进行微弧氧化,由于残余应力(200 MPa左右)较大,微弧氧化时表面氧化反应过程中促进了应力释放,使微弧氧化层加剧产生粗大裂纹;对打印后试样进行去应力热处理后,微弧氧化后表面仅见少量微小的工艺扩展裂纹.去应力后的微弧氧化层表面,平均摩擦因数由0.545降低到0.441,腐蚀环境后的抗腐蚀等级由9级提高到10级,证明3D打印激光立体成形热应力对成形零件的微弧氧化工艺性能影响较大.