Influence of Measuring Method on Young's Modulus and Comparison with Young's Modulus and Mechanical Property of Sintered Irons

摘要

In this study, the relationships between porosity and Young's moduli measured by an acoustic pulse method, a resonance frequency technique, a tensile test and a bending test of sintered irons were investigated. Moreover, tensile strength and proof stress were measured by tensile test, and these values and Young's modulus were evaluated against porosity. Young's moduli measured by the acoustic pulse method, resonance frequency technique and tensile test, except for the bending test, were nearly equal at the same porosity. In the case of the bending test, the moment of inertia of the area was a linear function of porosity. Young's modulus measured by the bending test, which was corrected by use of the above relation, was equal to that by other method. Young's modulus measured by the bending test was 0.7-0.8 times of Young's modulus measured by the tensile test. Young's modulus (E), tensile strength (T_S) and proof stress (P_S) against porosity (P) are expressed as E = (E_0 - K_E centre dot P) (1 - P), T_S = (T_(S0) - K_(Ts) centre dot P) (1-P) and P_S (P_(S0) - K_(Ps) centre dot P) (1 - P), respectively. Here, E_0, T_(S0) and P_(S0) are Young's modulus, tensile strength and proof stress at P=0, and K_E, K_(Ts), and K_(Ps) are the experimental coefficients of each relation. Moreover, we found that the relationships among Young's modulus, tensile strength and proof stress are in positive correlation.