摘要
在Ti811合金表面,利用同步送粉激光熔覆技术,制备了TC4激光熔覆层。利用X射线衍射仪、扫描电镜和能谱分析仪等手段分析了涂层组织和β相偏析行为。结果表明,涂层组织出现了典型的β相偏析现象,在涂层中以大块的暗色区域存在;涂层的非β相偏析区微观组织呈现出魏氏体结构,在α-Ti组成的晶界中分布着大量针状马氏体α′-Ti相和少量残留β-Ti相,纳米α_2相弥散分布在涂层中;涂层的β相偏析区域出现了大面积残留β-Ti相,晶界α-Ti相和针状马氏体α′-Ti相的特征和数量明显减少,主要是因为激光熔覆形成的熔池冷却速度极快,原始β晶粒来不及相变所导致。
The TC4 laser cladding layer was prepared on the surface of Ti811 alloys with coaxial powder feeding. The microstructure and β-phase segregation of the coating were analyzed by using X-ray diffraction （XRD）, scanning electron microscope （SEM） and energy dispersive spectrometer （EDS）. The results reveal that, the typical β phase segregation occurs in the cladding layer and appears as the large dark area. The microstructure of the non-β-phase segregation region of the cladding layer shows a typical widmanstatten structure. Many accicular martensitic α＇-Ti and trace residual β-Ti are distributed in the grain boundaries of α-Ti, and nano particles of α2 phase are dispersed in the cladding layer. In the β- phase segregation region of the coating, a large area of residual β-Ti appears in the microstructure while the grain boundaries of α-Ti and accicular martensitic α-Ti are obviously reduced, which are attributed to the molten pool formed by laser cladding cooling in a vary fast way and leaving no time for the phase transition of original β grains.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2018年第1期5-9,共5页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(51371125)
