Hot Deformation Behavior and Microstructure Evolution Mechanism of PM23/H13 Bimetal Produced by Hot Isostatic Pressing Powder‐Solid Diffusion Bonding

To investigate the hot deformation behavior of powder metallurgical high‐speed steel/alloy steel bimetal, uniaxial compression tests are performed on PM23/H13 bimetal under deformation temperatures of 1000–1150 °C and strain rates of 0.01–10 s −1 . A bimetal constitutive model based on strain compensation and friction correction is established and hot processing maps under different true strain levels are constructed. The results show that the average absolute relative error between the predicted and experimental flow stress values is only 3.62%. It is determined that the flow stress of PM23/H13 bimetal decreases with increasing deformation temperature and decreasing strain rate. The optimal hot processing window is identified as a deformation temperature of 1000–1100 °C and a strain rate of 0.01–0.1 s −1 . Electron backscatter diffraction analysis reveals that the bimetal exhibits typical dynamic recrystallization (DRX) characteristics at low strain rates, while displaying dual characteristics of dynamic recovery and DRX at medium to high strain rates. Scanning electron microscopy results clarify that the volume fraction of M 6 C and MC carbides on the PM23 powder metallurgical high‐speed steels side decreases with increasing deformation temperature and decreasing strain rate. This study provides a theoretical foundation for the industrial forging of such bimetal materials.