This study investigates the tensile behavior of AISI H13 hot work die steel at four distinct temperature points (25°C, 400°C, 500°C, and 600°C). An integrated approach combining experimental investigations with crystal plasticity finite element analysis elucidates the relationship between microstructure evolution and macroscopic mechanical properties. Experimental results show that yield strength decreases by 48.5% (from 1422 to 733 MPa) and ultimate tensile strength by 45.2% (from 1596 to 875 MPa) as temperature increased from 25°C to 600°C. Detailed metallographic observations of fracture surfaces and deformed regions reveal a progressive transition from quasi-cleavage fracture to ductile fracture as the temperature rises. Building upon these experimental insights, a temperature-dependent crystal plasticity finite element model is developed, incorporating both dislocation density evolution and strain-based damage accumulation. This model provides an accurate representation of the deformation behavior of AISI H13 steel across the temperature range studied. Through a comparison of experimental and simulated results, the validity and robustness of the model are confirmed. The model further unravels the underlying failure mechanisms, that at room temperature, tensile failure in AISI H13 steel is primarily driven by stress concentrations resulting from the multiplication and entanglement of dislocations. However, at elevated temperatures, the failure mechanism shifts toward grain softening and subsequent plastic deformation, which is facilitated by the annihilation of dislocations.
Wu et al. (Wed,) studied this question.