Microstructure and Mechanical Properties of Tib2/18ni300 Composite Material by Laser Additive Manufacturing

Abstract

As a reinforcing phase, TiB2 has good wettability and stability with the steel matrix, which is well suited as a reinforcement for steel matrix composites. In this paper, we add TiB2 for additive manufacturing of 18Ni300 steel for weight reduction and reinforcement. TiB2 reinforced 18Ni300 matrix composites were prepared by laser cladding. SEM, EDS, and XRD were used to observe the joints' interface and fracture characteristics and analyse the physical composition. Tissue analysis was then performed using EBSD and TEM. According to the TEM and XRD results, there is a martensite structure within the cell, and the cell boundary is an austenite structure. After adding TiB2, a reinforcing phase ((Mo, Fe)3B2) is distributed at the boundary of the cell structure. The high hardness of boride increases the microhardness of the composite material. The yield strength, modulus, and elongation of the samples prepared with 18Ni300 powder are lower than that of forged 18Ni300, but the tensile strength reaches 1134 MPa. The addition of TiB2 increases the composite material's yield strength and elastic modulus significantly. This experiment provides a theoretical basis and process reference for preparing high-stiffness and lightweight ceramic particle reinforced metal matrix composites.

Keywords: Laser cladding, Steel matrix composite, 18Ni300, TiB2, Mechanical properties