摘要
High niobium β-γ TiAl alloy(HNBG) was diffusion bonded using spark plasma sintering with pure Ti as interlayer. The joint microstructural evolution, growth kinetics and mechanical properties were investigated. The joint included three diffusion zones. The β/B2 phase formed in the Zone Ⅰ, α_(2)phase in the Zone Ⅱ, and β-Ti and α-Ti phases in the Zone Ⅲ. The thickness of β/B2 phase, the average grain size of α_(2)phase and the amount of β-Ti phase increased with the increase of bonding temperature or bonding time. The growth activation energies of β/B2 and α_(2)phases were 582 and 253 kJ/mol, respectively. The joint acquired at 1000 °C, 10 min and 10 MPa showed the maximum shear strength of 308 MPa. Fracture mainly occurred along the interfaces between Zone Ⅰ and HNBG alloy, and between Zone I and Zone Ⅱ. Fracture mechanism of the joint was characterized by brittleness rupture along the phase boundary.
采用放电等离子烧结技术,以纯钛为中间层,对高铌β-γ TiAl合金(HNBG)进行扩散连接,对接头的显微组织演变、生长动力学和力学性能进行研究。接头包括三个扩散区,分别是Ⅰ区形成β/B2相,Ⅱ区形成α_(2)相,Ⅲ区形成β-Ti相和α-Ti相。β/B2相的厚度、α_(2)相的平均晶粒尺寸和β-Ti相的含量随着连接温度或时间的增加而增加。β/B2相和α_(2)相的生长活化能分别为582和253 kJ/mol。在1000℃,10 min,10 MPa下接头达到最大剪切强度308 MPa。断裂主要发生在扩散区I和HNBG合金之间以及扩散区I和扩散区Ⅱ之间的界面上。HNBG合金接头的断裂机制为沿着相界的脆性断裂。
基金
supported by the National Natural Science Foundation of China (Nos. 51871012, 52071021)
Beijing Natural Science Foundation (No. 2162024)
Fundamental Research Funds for the Central Universities, China (No. FRF-GF-20-20B)
the National Key Basic Research Program of China (No. 2011CB605502)。
