TiAl合金表面激光重熔等离子喷涂MCrAlY涂层研究

为了进一步提高TiAl合金表面等离子喷涂MCrAlY涂层的高温氧化性能,采用激光重熔工艺对涂层进行处理,研究了激光重熔对涂层微观组织及抗氧化性能的影响.用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分析了涂层氧化前后的表面形貌、微观组织和相组成.结果表明:经过激光重熔处理后,涂层片层状组织得以消失,致密性提高,消除了喷涂层的大部分孔洞、夹杂等缺陷,同时使Al元素在涂层表面的重新分布,形成了Al的富集区;等离子喷涂MCrAlY层能显著提高TiAl合金的抗高温氧化性能,经过激光重熔后可进一步提高其抗高温氧化性能.

Study on Laser Remelting MCrAlY Coatings Prepared by Plasma Spraying on TiAl Alloy Surface

To improve the hightemperature oxidation resistance of the MCrAlY coatings prepared by plasma spraying on TiAl alloy surface, laser remelting experiment had been carried out and the effects of laser remelting on microstructure and oxidation resistance on the coatings were researched. The surface morphology, microstructure and phase of the coatings before and after oxidation were investigated using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometry (XRD). The results show that the coating has a higher compactness and the lamellar structure of plasma-sparyed coating is eliminated after laser remelting. Meanwhile, aluminum is redistributed at the top of the remelted coating and forms an Al-rich region because of relative low density of Al. The plasma-spayed MCrAlY coating has better oxidation resistance than the original TiAl alloy, and the laser-remelted coating has the best oxidation resistance.