Failure analysis and mechanical reliability of cast higher manganese silicide

This work focuses on the correlation between microstructure and mechanical properties of higher manganese silicide (HMS). A single crystal HMS ingot was cast from elemental Mn and Si with a nominal composition of Mn15Si26. The microstructure of the ingot was characterized, and its fracture strength was evaluated following ASTM C1161 bending test. The correlations between elastic modulus, fracture strain, fracture stress and toughness were studied and Weibull distribution analysis was applied to fracture strength data. Statistical results show a wide distribution in the mechanical prosperities. Fractography reveals the profound effect of the minority MnSi phase on the failure mechanism of HMS. The negative effect of the minority second phase MnSi particles on the mechanical reliability of HMS is highlighted.