PM-TZM钼合金电子束焊接特性

为研究PM-TZM钼合金电子束焊接特性，对其进行了电子束焊接试验，分别对接头显微组织及力学性能进行了分析. 结果表明，PM-TZM钼合金电子束焊缝呈“钉状”几何特征，熔合线附近有链状气孔出现. 焊缝区由粗大的等轴晶及柱状晶组成，热影响区晶粒相比于母材明显长大. 接头各区域硬度值不同，焊缝区硬度与母材相当，硬度最低值出现在两侧热影响区.PM-TZM合金电子束焊接接头有较大的性能损失. 接头室温最高抗拉强度378 MPa，为母材抗拉强度的47%，1 000℃抗拉强度168 MPa. 接头拉伸断裂均发生于焊缝区，呈典型的脆性解理断裂特征.

Weldability of PM-TZM alloy using electron beam welding

Weldability of PM-TZM molybdenum alloy using electron beam welding (EBW) was investigated in this study. EBW experiments on PM-TZM plates were carried out and microstructure and mechanical properties of the welded joints were analyzed. The results showed that the cross section of the weld zone (WZ) had a nail-like shape with the welding pores distributed along the fusion line. The WZ was composed of the coarsened equiaxed grains and columnar grains. The grains in heat affected zone were coarser than those in matrix area. Microhardness of joint presented an uneven distribution where the microhardness of the WZ was at the same level compared with the BM and the HAZ had the lowest microhardness. The tensile strength of the joint reduced sharply after welding compared to the BM that the room temperature tensile strength of the joint was 378 MPa which was 47% of BM. Tensile strength of the joint performed at 1 000 ℃ was 168 MPa. The tensile test fracture located at WZ and the weld fracture presented characteristics of cleavage fracture.