Enhanced high-temperature wear resistance of GCr15 steel balls by generating a Ti + Nb diffusion layer via mechanical alloying and NH3·H2O treatment

Abstract

In this study, mechanical alloying and NH3·H2O treatmentGCr15 steel balls were used to strengthen GCr15 steel balls. The steel balls were first coated with a Ti + Nb coating using a ball mill equipped with a homemade grind jar, followed by a NH3·H2O treatment in a common jar to remove the Ti + Nb coating. Surprisingly, a Ti + Nb diffusion layer with a thickness of 5.1 μm was generated. The mechanical properties of both processed samples and unprocessed samples were investigated, including grains, dislocations, microhardness, residual stress, and friction properties at different temperatures. The results showed that the processed sample had obvious grain refinement and large dislocation density, with maximum microhardness and compressive residual stress values of 934 HV and − 490 MPa, respectively. Additionally, the processed samples exhibited exceptional high-temperature wear resistance, with a remarkable decrease in friction coefficient to 0.26 at 400 °C, which was 52.73 % less than that of unprocessed samples. These results highlight the potential of this method for improving the high-temperature resistance of various mechanical components, particularly steel balls.