热处理态Ni-Cr-Al合金的拉伸性能及微观变形机理

Ni-Cr-Al alloy was prepared by electron beam vapor deposition, further solution treated and aged, then its tensile behaviors and dislocation configuration characteristics under different temperatures in range of 20-1000 ℃ were investigated. The experimental results indicate that as the temperature increases, the tensile strength of the alloy decreases gradually, and the fracture morphology becomes mostly dimpled and quasi-cleavage fracture. At room temperature, when the γ' particles in the alloy reach the critical size, the dislocation bending bypasses the γ' particles. At 400 ℃, the dislocation density increases and the defect interface forms an external stacking fault, while the existence of an antiphase domain boundary increases the resistance of dislocation cutting through γ' particles. At 700 ℃, dislocations can bend and move along the matrix, resulting in climbing and cross-slip. At 1000 ℃, the dislocation lines become longer and bend, resulting in the formation of dislocation rings surrounding γ' particles.