TC合金粉末热等静压零件表面形貌研究

Study on surface morphology of TC4 alloy powder produced by hot isostatic pressing

对等离子旋转电极(PREP)法制备的TC4合金粉末,采用扫描电镜(SEM)及能谱仪(EDS),研究了两种热等静压(HIP)工艺下TC4零件表面形貌和表面附近微观组织.结果表明:同时升温升压的HIP工艺得到宏观波浪状致密零件表面,波峰呈圆形,波谷存在尖角,表面轮廓最大高度不超过最大粉末颗粒半径,零件表面与内部组织相同,主要是典型细小板条状α+β组织;先升温后升压的HIP工艺得到宏观平直的致密零件表面,表面粗糙度与控形型芯表面粗糙度相当,零件表面附近为等轴细晶区,零件内部为粗大魏氏体组织;两种HIP工艺得到的TC4零件表面均未发现明显的控形型芯元素扩散.

The surface morphology and microstructure of TC4 parts with two procedures of hot iso-static pressing （HIP）process were studied.The TC4 alloy powder was prepared by plasma rotating e-lectrode process （PREP）.The scanning electron microscopy （SEM）and energy dispersive spectrosco-py （EDS）methods were used.The results show that when temperature and pressure increase simulta-neously during HIP process,dense parts with micro-wave surfaces are obtained with round crests, troughs with sharp corners and the maximum height Rz of the surface profile is less than the maximum powder particle radius.The TC4 parts is mainly the same fine lathα＋βstructure,when the HIP tem-perature is elevated before pressure,dense parts with macro-straight surfaces are obtained with the surface roughness comparable to that of the shape-control mold.Near surface zone of part is mainly the equiaxed grain,and the inner was coarse Widmanstatten structure.Obvious diffusion of shape control mold elements is not found in the TC4 parts surfaces obtained from the two HIP procedures.