Effect of Heat-Treatment and Cold-Drawing on the Microstructure and Mechanical Properties of MP35N Alloy

To investigate the effects of cold drawing and heat treatment on the microstructure and mechanical properties of MP35N cobalt-based alloy, hot-rolled, solid solution, and cold drawn states of MP35N Co-based alloy was obtained through different processing methods. The influence of different processing techniques on the microstructure and mechanical properties of alloys was studied. The research results showed that the hot-rolled state exhibited uniform and fine-grained microstructure with yield strength of 567 MPa, elongation of approximately 20%, and hardness of 22.9HRC. After solution treatment at 1020 °C, the grain size was rapidly growth, leading to the d yield strength and hardness reduction. On the contrary, the strength and hardness of the cold drawn alloy have been greatly improved. The yield strength and hardness increased significantly from 368 MPa and 8.5HRC to 1501 MPa and 49.1HRC, respectively. This improvement was primarily attributed to work hardening induced by cold drawing deformation, which generated numerous deformation twins and dislocations, thereby substantially elevating the alloy’s strength and hardness.