(中国科学院 金属研究所，沈阳110016)
摘 要: 采用电子束焊接工艺研究Ti-22Al-24Nb-1Mo合金厚度为0.6 mm冷轧板的焊接性，用电子探针观察焊后焊接接头处的合金元素分布情况，通过光学金相显微镜、扫描电镜和透射电子显微镜对等对焊后及焊后热处理的焊接接头区域显微组织演变和相组成的变化进行了分析，利用维氏显微硬度计测试焊后及焊后热处理的焊接接头区域的显微硬度。结果发现：该合金板材具有良好的焊接性能，焊接接头未产生焊接缺陷；Al元素有一定程度的烧损，焊缝熔合区由柱状B2相晶粒组成；经焊后热处理，熔合区组织转变为(O+β)网篮组织；焊后及焊后热处理均为热影响区的硬度值最高；经焊后热处理，焊接接头的硬度显著提高。
关键字: Ti2AlNb合金；电子束焊接；接头；组织
（Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The weldability of the Ti-22Al-24Nb-1Mo alloy cold rolled sheet with thickness of 0.6 mm was investigated by electron beam welding, and the element distribution was observed across the weld joint using electron probe micro-analyzer (EPMA). The microstructure of the joints and its phase evolution characterization after heat treatment were investigated by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Vickers microhardness across the as-weld and heat treated joints was tested. The results indicate that this alloy sheet has good weldability and no defect forms in the joints. The aluminum depletion is observed in the bulk of the fusion zone. The fusion zone (FZ) of the as-weld joints is composed of metastable ordered β phase (namely B2 phase), and after heat treatment, the B2 phase decomposes to O phase and disordered β phase, a basket wave microstructure forms. The microhardness of the heat-affected zone is higher than the base metal and fusion zone, and after heat treatment, the microhardness is elevated significantly.
Key words: Ti2AlNb alloy; electron beam welding; joints; microstructure
