Effects of carbon fibers on the microstructure and properties of laser cladding 24CrNiMoY alloy steel

Abstract 24CrNiMoY alloy steel is widely used as a raw material for manufacturing wear-resistant parts, but its low microhardness can’t meet the service requirements of the surface working layer of the parts. Therefore, laser cladding technology was used to prepare carbon fibers (CFs) reinforced alloy steel samples with different CFs content (0−1 wt.%). The results showed that as the CFs content increased, the microstructure of the samples gradually changed from lath bainite (LB) to lath martensite (LM), and finally to plate martensite (PM). The microhardness and tensile strength of samples showed a trend of increasing first and then decreasing. When the CFs content was 0.8 wt.%, the microhardness was 835 HV0.2, reaching the peak value, which was 133.9 % higher than that of 24CrNiMoY alloy steel. Besides, when the CFs content was 0.6 wt.%, the comprehensive mechanical properties were the best. Compared with 24CrNiMoY alloy steel, the average microhardness and tensile strength increased by 113.2 % and 29.4 %, respectively, reaching 761 HV0.2 and 1061.14 MPa. The research results indicated that the microhardness and wear resistance of 24CrNiMoY alloy steel were significantly enhanced by adding a small number of CFs, which provides a reference for laser cladding parts with high microhardness surface working layer.