激光沉积制备A15-Nb_3Al/B2叠层金属间化合物复合材料  

A15-Nb_3Al/B2 Laminated-Structure Intermetallic Composites Produced by Laser Deposition

作　　者：钟敏霖[1] 何金江[1] 刘文今[1] 张红军[1] 郝倩[1] 

机构地区：[1]清华大学机械工程系激光加工研究中心先进成形制造教育部重点实验室,北京100084

出　　处：《中国激光》2007年第12期1694-1699,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(10477009)资助项目

摘　　要：铌基金属间化合物是一种潜在高温结构材料,室温脆性大。用Nb-12Ti-22Al和Nb-40Ti-15Al两种混合粉末,经激光沉积分别合成制备了A15-Nb3Al金属间化合物脆性涂层和韧性B2结构合金涂层。通过对制备工艺的研究,基本实现了每层成分和层厚的控制,利用韧脆相间层层叠加方法用激光制备出不同层厚比的脆韧相间A15-Nb3Al/B2叠层结构金属间化合物基复合材料。叠层复合材料的元素成分、显微组织和显微硬度均呈周期性变化,界面存在渐变过渡。叠层结构Nb基金属间化合物复合材料具有良好的室温和高温强度,性能呈各向异性。随着脆韧层厚比的增大,叠层复合材料的强度增加,在水平、竖直两方向的室温屈服强度最高分别可达1030 MPa和871 MPa,900℃屈服强度最高分别为301 MPa和267 MPa。Niobium-based intemetallic composite is a kind of potential high temperature structural material. However, it is very brittle at room temperature. Laser deposition was used to synthesize A15-Nb3Al intemetallic brittle coating arid B2 structure tough alloy coating by using Nb-12Ti-22Al and Nb-40Ti-15Al powder blends, respectively. By deposition technique optimization, the composite of the coating and layer thickness can be controlled. An A15-Nb3 A1/B2 laminated-structural intermetallic composite material was then produced via layer by layer deposition method. The element composition, microstructure and microhardness of the laminated intermetallic composite show periodic variation,and gradual change at the interface between two neighboring layers. This material demonstrates good strength at room and elevated temperature. The yield strengths of laminated composites increased with the brittle/ductile layer thickness ratios. The horizontal yeild strengths reach up to 1030 MPa and 301 MPa at room temperature arid 900℃, and the vertical yeild strengths reach up to 871 MPa and 267 MPa at room temperature and 900 ℃.

关 键 词：激光技术 激光沉积 Nb-Ti-Al 叠层复合材料 金属间化合物 

分 类 号：TG665[金属学及工艺—金属切削加工及机床]