Residual stresses in Cu matrix composite surface deposits after laser melt injection

Abstract

Metal matrix composite (MMC) coatings can improve surface wear resistance significantly. However, both macro and micro residual stresses exist in the MMC coatings, causing detrimental effects such as reducing service life. Based on neutron diffraction, we measured the residual stresses in the spherical fused tungsten carbide (sFTC) reinforced Cu matrix composite surface deposits after laser melt injection. Thermo-mechanical coupled finite element model was also developed to predict the residual stresses. We found that the residual stresses are low in the sFTC/Cu composite deposit produced with 400 °C preheating temperature, with a maximum tensile residual stress of 98 MPa in the Cu matrix on the top surface. In contrast, the residual stresses in the sFTC/bronze (CuAl10Ni5Fe4) composite deposit are very high. The maximum tensile residual stress in the Cu matrix of the sFTC/bronze composite deposit reaches 651 MPa on the top surface. The present investigations can help the researchers to control the residual stresses in the Cu matrix composite surface deposits and increase the service life of wear-resistant coatings in the future.