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采用电子束物理气相沉积(EB-PVD)制备出大尺寸、超薄、化学成分均匀的TiAl/Ti_3Al微叠层复合材料.通过XRD和SEM对材料的相组成和微观结构进行了分析.结果表明:TiAl/Ti_3Al微叠层表面状态良好,具有明显的层状结构,相结构由a2-Ti_3Al和g-TiAl组成.利用热等静压技术对微叠层进行了致密化处理,经热等静压处理后的试样具有较高的拉伸强度,并表现出较好的延伸率.根据拉伸断口形貌及结构特征,探讨了微叠层材料薄板的微观变形机制和断裂机理.TiAl/Ti_3Al微叠层薄板经热等静压处理后,材料断裂方式由沿晶脆性断裂转变为具有一定韧性的准解理断裂和沿晶脆性断裂的混合断裂方式.
The TiAl / Ti3Al micro-layered composite with large size, ultra-thin and uniform chemical composition was prepared by electron beam physical vapor deposition (EB-PVD). The phase composition and microstructure of the composite were analyzed by XRD and SEM. The microstructure of TiAl / Ti_3Al micro-stack is well-surfaced with obvious lamellar structure and the phase structure consists of a2-Ti_3Al and g-TiAl. The micro-stack is densified by hot isostatic pressing technique, The microstructures and fracture mechanisms of microlaminated sheets were discussed according to the tensile fracture morphology and the structural features of the samples after pressure treatment.The tensile strength and the elongation of TiAl / After hot isostatic pressing, the fracture mode of the Ti_3Al micro-laminated sheet changed from brittle fracture to quasi-cleavage fracture with a certain toughness and mixed fracture mode along the brittle fracture.