Microstructure and Mechanical Properties of H13 Steel/High-Speed Steel Composites Prepared by Laser Metal Deposition

In engineering applications, optimizing the properties of die steel has long been a focus of research. The use of composite materials, which can effectively improve the performance of materials, is a potential method to improve the properties of die steel. In this research, near defect-free block H13/W-Mo-V high-speed steel (HSS) composites were fabricated by laser metal deposition. The microstructure, phase, hardness and wear resistance were measured as a function of the composition of the composite and were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDS), hardness testing and wear testing. The results show that the microstructures of all samples consisted of martensite, retained austenite and carbides. Carbide particles were found in the grain boundaries when the W-Mo-V HSS content reached 40%. As more W-Mo-V HSS was added, these carbides aggregated to form a continuous network. The microhardness of the composites improved as the W-Mo-V HSS content increased from 541 to 799 HV. The hardening phase of martensite was tested by nanoindentation. The changes in the nanohardness were similar to those of the microhardness. In addition, the wear performance of H13 steel significantly improved when it was mixed with W-Mo-V HSS to form a composite.