Simultaneous improvement of strength and plasticity of TZM alloys by introducing α-Al2O3 ceramic particles

A new α-Al2O3 ceramic particles reinforced TZM alloy material was prepared by powder metallurgy, exhibiting a better combination of strength and plasticity. Comprehensive tensile tests and detailed microstructure observations showed that compared with the TZM alloy. The ultimate tensile strength and uniform elongation of the TZM-0.9 wt% Al2O3 alloy increased by 22 % and 55 %, respectively, and all the strengthened TZM alloys exhibited typical toughness fracture characteristics. Based on theoretical analysis, strengthening is mainly caused by the mismatch of the elastic modulus between α-Al2O3 ceramic particles and the molybdenum matrix, accounting for 71 % of the increase in total strength. Mismatch of the elastic modulus can increase the dislocation density of the matrix around α-Al2O3 particles. In addition, α-Αl2O3 particles promote the rotation of grains along the <111> direction during plastic deformation, leading to activation of the slip system and promotes the improvement of plasticity.