Effect of heat treatment on microstructure and mechanical properties of tantalum by selective laser metal

Abstract

Improving the mechanical properties of selective laser–melted pure tantalum (SLMed Ta), a new-generation orthopedic implant material, is of paramount importance. Appropriate annealing parameters directly affect the microstructure and macromechanical properties of SLMed Ta, thereby making them a focal point in the research on this material. This study conducted a gradient crossover experiment to elucidate the effects of three annealing temperature ranges and holding times on the grain morphology and mechanical properties of SLMed Ta. The results indicated that in the low-temperature annealing section (700 °C–900 °C), the tensile strength of the samples progressively increased with rising annealing temperatures. In the recrystallization annealing section (1100 °C–1300 °C), the recrystallization of the samples increased, with a tensile strength of 610.67 ± 11.16 MPa at 1100 °C annealing for 4 h, representing a 34.51 % improvement compared to the unannealed state. In the high-temperature annealing section (1500 °C), the average tensile strength increased, and the elongation after fracture demonstrates a decrease, As a result of oxygen segregation. Extending the holding time from 2 h to 6 h resulted in the formation of more subgrains. This study provides critical insights into the optimization of annealing parameters for improving the mechanical properties of SLMed Ta, thereby advancing its application potential in orthopedic implants.