An improved analytic model for extracting plastic mechanical property of matrix in hot-extruded in-situ TiB2/2024 composite based on Berkovich indentation experimental results

Due to the strengthening mechanisms mainly contributed to dispersed nano TiB2 particles, plastic mechanical property of Al matrix in hot-extruded in-situ TiB2/2024 composite, referring to yield strength (YS) and strain hardening exponent (SHE), are considerably improved compared with 2024 Al alloy. In addition, the plastic mechanical property of Al matrix cannot be obtained directly through traditional uniaxial tensile tests. After carrying out dimensional analysis and FE simulations, an improved analytical model with no need of characteristic stress/strain is proposed found on existing model, to extract plastic mechanical property parameters of Al matrix based on sufficient Berkovich indentation experimental results. The indentation experiments carried out using the custom method “G-Series Basic Hardness, Modulus, Tip Cal, Load Control” were implemented in case of four different maximum indentation loads to get indentation load-depth curves (ILDCs) of Al matrix, where the corresponding morphologies of residual indents were obtained by SEM observation. With these experimental results as input, the YS and SHE of Al matrix can be calculated by utilizing the proposed analytic model. To verify the effectiveness of proposed improved model, a unit-cell FE model with same particle volume fraction as the macroscopic composite is established and analyzed, and the calculated results are in good agreement with the uniaxial tensile test results.