Relations of porosity to Young's modulus and tensile strength and correlations between those mechanical properties of sintered steels

Young's modulus (E) and tensile strength (S) of sintered steels depend mainly on porosity (P). The relations of P to E and S are described as E = (E₀ - E_sub)exp(- b_E · P) + E _sub and S = (S₀ - S_sub) exp(- b_s · P)+S_sub, respectively, Where E₀ and S₀ mean the mechanical properties at P=0, E_sub, b_E, S _sub, and b_s are experimental constants. The E _sub and b_E are affected by pore characteristic, such as pore shape, size, and interconnection, and S₀, S_sub, and b_s depend on not only the pore characteristic but also metal matrix structure. The fitting curves of shear modulus and 0.2% proof stress used by the above relation of P also correspond to the measured values of them, respectively. And then, Poisson's ratio calculated by the above relatons of Young's and shear moduli correspond to the measured value in comparison with Poisson's ratio calculated by the fitting equation, the type of E = E ₀ exp(- b_E · P), of each modulus. Furthermore, the relationship between ln(S - S_sub) and ln(E - E_sub) of sintered steels shows the positive linear correlation.