摘要
利用一种全新的激光等离子同时复合喷涂加工技术,成功在AZ91D镁合金表面制备了Al-Si/Al+Al2O3涂层,并研究了激光功率对涂层结构和性能的影响。利用SEM、光学显微镜法、XRD、显微硬度计等分析测试手段研究了在不同激光功率下的涂层形貌、孔隙率、相组成、显微硬度。结果表明:Al-Si过渡层明显改善了涂层与基体的结合,当激光功率为1800W时,涂层中未熔颗粒最少,涂层最致密;涂层仅存在Al和稳定态α-Al2O3两种相,没有残留的亚稳态γ-Al2O3相;涂层的孔隙率随着激光功率的增加而降低,由4.5%降低到2.6%,但激光功率超过1800W时,涂层孔隙率不降反而增加;喷涂后,硬度由HV0.0555增加到HV0.05275,涂层表面的显微硬度最大,并随激光功率的增加而增加,但当激光功率增加到2000W时,涂层硬度不再增加反而略有降低。
An Al-Si/Al＋Al2O3 coating was prepared on the AZ91D Mg alloy substrate by a new processing technique of laser plasma and with the combination of spraying,and the influences of the laser power to the structure and properties of the coating were studied.X-ray diffraction（XRD） and scanning electron microscope（SEM） were used to identify the phases and to study the morphology respectively.By the porosity ratio of the coating material was measured by using an optical microscope（OM） and the microhardness was measured using a micro Vickers hardness tester.The results show that the Al-Si transition layer improves the adhesion of the coating obviously.When the laser power is 1800W,the unmelted particles are less and the coating is the densest.The coating is composed of Al phase and α-Al2O3 phase and no surviving γ-Al2O3 phase existed.The porosity ratio decreases from 4.5% to 2.6% with the increase of the laser power.But when the power is more than 1800W,the porosity ratio increases.The hardness increases from HV0.0555 to HV0.05275 after spraying.The hardness of the surface is the largest and increases with the increase of the laser power.But when the power increases to 2000W,the hardness has no big change.
出处
《航空材料学报》
EI
CAS
CSCD
北大核心
2011年第3期60-64,共5页
Journal of Aeronautical Materials
基金
航空科学基金资助项目(20085451039)
