V4Cr4Ti合金和RAFM钢的热等静压扩散连接及其界面特性

低活化铁素体/马氏体(reduced activation ferritic/martensitic，RAFM)钢及钒合金被认为是未来核聚变反应堆第一壁的候选结构材料，性能各有优劣，可满足近中期应用要求. 采用热等静压技术在温度800 ℃、等静压压强150 MPa和保温时间2 h下实现V4Cr4Ti合金和CLF-1钢的固态扩散连接，对其界面微观组织、元素扩散特征以及抗剪强度进行了分析. 结果表明，CLF-1钢在距离连接界面120 μm区域内出现脱碳层，而V4Cr4Ti合金侧存在宽度约1.5 μm的高硬脆碳化物层；V4Cr4Ti合金/CLF-1钢连接界面无缺陷，接头室温抗剪强度最高达238 MPa. 断口分析表明，断裂发生于靠近V4Cr4Ti合金侧的高硬脆碳化物层，断口表现出整体韧性，局部脆性断裂的特征.

Hot isostatic pressing diffusion bonding of V4Cr4Ti alloy/RAFM steel and interface properties of the joints

Reduced activation ferritic/martensitic (RAFM) steels and vanadium alloys are considered as candidate structural materials for the first wall of fusion reactors in the future, with their own advantages and disadvantages, which can meet the requirements of short-term and medium-term applications. In this study, hot isostatic pressing technology was used to connect V4Cr4Ti alloy and RAFM steel CLF-1 at the hot isostatic pressure parameters of temperature 800 ℃, isostatic pressure 150 MPa and holding time 2 h, and the interface microstructure, element diffusion characteristics and shear mechanical properties were analyzed. The results show that a decarburized layer is present in the CLF-1 steel within a distance of 120 μm from the connection interface, while a high-hard brittle carbide layer with a width of about 1.5 μm exists on the V4Cr4Ti alloy side. The V4Cr4Ti alloy/CLF-1 steel connection interface has no defects, and the room temperature shear strength of the joint is up to 238 MPa. The fracture analysis results show that the fracture occurs in the high-hard brittle carbide layer at the vanadium alloy side, and the fracture shows the characteristics of overall toughness and local brittle fracture.