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The addition of WC particles has the potential to improve the properties of 18Ni300 alloy, but the effect of heat treatment on the microstructure and mechanical properties of 18Ni300 matrix composites needs to be further investigated. In this work, WC-reinforced 18Ni300 composites were fabricated using laser powder bed fusion (LPBF). The composites were made into solutions at 846 °C for 51 min, followed by aging at 388 °C for 300 min. The microstructural evolution and compressive properties of the composites before and after heat treatment were systematically studied. The results indicate that the microstructures of the composites consist of heterogeneous cellular and fine columnar grains. As the WC content increases, the primary phase in the LPBF-formed samples gradually shifts from α-Fe martensite to γ-Fe austenite. After heat treatment, the primary phase transforms to α-Fe with only a small residual amount of γ-Fe. The microstructure becomes more uniform, featuring a significant reduction in grain size. Many precipitated phases can be found in the intergranular, accompanied by an increase in the thickness of diffusion layers. The WC content in the composite material is positively correlated with its hardness and compressive strength. As the WC reinforcement content increases from 5% to 20%, the yield strength and compressive strength of the LPBF-formed composites increase to 1042.5 MPa and 2900.7 MPa, respectively, while the compressive elongation decreases from 64% to 43%. After heat treatment, the yield strength of the composites significantly increases to 2356.8 MPa, with a slight increase in the compressive strength to 2939.7 MPa. However, the elongation decreases from 32.5% to 22%. [ABSTRACT FROM AUTHOR]

Different contents of WC particle‐reinforced 18Ni300 composites are prepared by selective laser melting method, and the tribological properties are comparatively studied before and after solution aging heat treatment. The results show that a part of WC particles are dissolved, and no obvious pore defects appear. With the increase of WC content, the microstructure gradually transforms from cellular and fine columnar α‐Fe martensite to γ‐Fe austenite. After solution aging heat treatment, the phase is transformed into acicular martensite. The grain size significantly decreases, and the Vickers hardness increases. The grain size decreases and the hardness increases with increasing WC contents. For the as‐built composite, the friction coefficient first decreases and then increases, and the wear rate first increases and then decreases with the increase of WC content. With WC content increasing, the wear rate first decreases and then increases. After heat treatment, the tribological properties are improved. The groove of the specimens before heat treatment is deep with large delaminated craters, and the wear mechanism is dominated by adhesive and abrasive wear. The grooves become shallower, and the adhesive trace becomes lighter after heat treatment. The wear mechanism is mainly adhesive wear and abrasive wear, accompanying with oxidative wear. [ABSTRACT FROM AUTHOR]

Metal‐polymer composites can be used to synthesize material properties. A variety of interpenetrating phase composites have been produced by spontaneously infiltrating porous short‐fiber preforms with unsaturated polyester resin under vacuum conditions. Porous preforms are fabricated by compacting and sintering short 304 stainless steel fibers from cutting stainless steel fiber ropes. Tensile experiments are conducted, and fractographs are examined via scanning electron microscopy. The results reveal that the tensile strength, elongation at maximum stress, and elasticity modulus of the IPCs increase with the increasing fiber fractions and exhibit anisotropy in different directions. The tensile strength and elongation at maximum stress are significantly improved compared with the consistent preforms. A nonlinear elastic behavior and sawtooth‐like fluctuation during yield deformation are noted. Compared with the through‐thickness direction, a higher tensile strength and larger elongation at maximum stress are observed in the in‐plane direction. Finer‐diameter fibers can improve the strength and increase the elongation at maximum stress. The tensile fracture surfaces show a mixture of brittle and plastic fracture characteristics. [ABSTRACT FROM AUTHOR]