Strengthening mechanisms of AlCoCrFeNi-WC-Ti coating from first-principles calculations

Abstract

The AlCoCrFeNi-WC-Ti composite coating exhibits excellent hardness and wear resistance, which mainly comes from the various strengthening mechanisms. An accurate prediction model is crucial for analyzing the hardness contribution of various strengthening mechanisms. In this study, AlCoCrFeNi and AlCoCrFeNiW 0.5 supercells were constructed by the special quasi random structure (SQS), and then the elastic moduli were obtained by first-principles calculations. Using the elastic moduli, a predicted model was established for the hardness contribution. The results showed that the shear modulus of AlCoCrFeNi and AlCoCrFeNiW 0.5 alloys is 80.43 GPa and 68.64 GPa, respectively. Solid solution strengthening with a hardness contribution of 248.5 HV is the dominant strengthening mechanism for the AlCoCrFeNi-WC-Ti composite coating. The sum of hardness contribution is 271.4 HV from various strengthening mechanisms. And compared with the Vickers hardness, the relative error is only 7.4%. For the AlCoCrFeNiW 0.5 alloy, namely the coating matrix (CM) of the AlCoCrFeNi-WC-Ti, its sum of hardness contributions is 251.2 HV. Compared with the nanoindentation hardness, the relative error is 4.8%, which indicates that the predicted model is accurate for the hardness contribution. The mechanical constants of AlCoCrFeNi and AlCoCrFeNiW 0.5 SQS supercells were calculated by first-principles calculations. Using the mechanical constants, an accurate prediction model was established for the hardness contribution. • The mechanical constants of AlCoCrFeNi and AlCoCrFeNiW 0.5 were calculated by first-principles calculations. • The shear modulus is 80.43 GPa, and 68.64 GPa, for AlCoCrFeNi, and AlCoCrFeNiW 0.5 , respectively. • The sum of hardness contributions is 275.5 HV from various strengthening mechanisms. • The relative error is only 5.8% between the predicted hardness and the Vickers hardness.