Finite element method-assisted acquisition of the matrix influence on the indentation results of an embedded hard phase

FE-simulations were performed in order to quantify the matrix influence on the load–displacement curve and thus on the apparent hardness and Youngʹs modulus of an embedded hard phase. The model system investigated in this study is the cold work tool steel X210Cr12 with an embedded spherical M7C3 carbide. In order to investigate the matrix influence on the indentation results, two different heat-treatment conditions were distinguished (soft-annealed and quenched+tempered). For each material combination, as well as several hard phase diameters, load–displacement curves and mechanical properties were calculated (via traditional Oliver and Pharr method) [1]. For low hard phase sizes or deep indentation depths, the surrounding matrix undergoes plastic deformation as the hard phase is pushed into it. This push-in event leads to significant errors in the calculated material parameters. A critical maximum indentation depth was determined depending on the hard phase diameter. It is shown that the ratio of indentation depth and hard phase diameter is the quantity of importance.