Dislocation Structure and Fracture Characteristics of Spray Deposited Ni3Al-Mo Intermetallic Compound Alloy (IC6)

A Ni3Al-Mo intermetallic compound alloy (IC6) was prepared by the multifunctional spray atomization and deposition plant. Tensile properties tests indicate that the spray deposited Ni3Al-Mo alloy possesses “R” characteristics in the yield strength, that is, the yield strength of the spray deposited IC6 increases with increasing of temperature and it reaches maximum at 760 °C. After that, it decreases with increasing of temperature. Analyses of dislocation structure by TEM reveal the relationship between the microstructure and yield strength. The results show that the change of the yield strength of the alloy with temperature is associated with the condition of dislocation winding, the pattern and quantity of the dislocation pairs and starting degree of the hexahedron slip system inside γ′ and γ phases. The TEM analysis of cracking by stereographic projection shows that with the increase of deformation stress the cracks form at grain boundaries and then quickly propagate, and some different slip bands exist in little planar zones; no matter at room temperature, middle temperature or high temperature, cracks craze along (111) plane octahedron slip.