Effect of raw materials ratio on performances of porous MgO reinforced Fe-Cr-Ni composites

Abstract

Fe-Cr-Ni alloys are widely applied to aero-engine, industrial gas turbine and other equipment because of their high temperature strength and toughness and creep resistance. Four kinds of porous MgO reinforced Fe-Cr-Ni matrix composites, which are nano-MgO (34.9%)/Fe-Cr-Ni (mass fraction, the same below), micro-MgO (34.9%)/Fe-Cr-Ni, micro-MgO (25.7%)/Fe-Cr-Ni, micro-MgO (17.0%)/Fe-Cr-Ni, were prepared by powder sintering and in situ synthesis method. Effect of the particle sizes and content of MgO on bending strength at room or high temperature and oxidation resistance of porous metal matrix composites at high temperature were investigated by XRD, DTA and SEM. The results show that different raw materials lead to the different enthalpy, resulting in the different porosities and phase compositions for the sintered samples. The porous composites consist of Cr0.7Fe0.36Ni2.9, Cr-Fe and MgO phases generally. The bending strength of these porous composites decreases with the increase of the temperature. The high temperature oxidation resistance of nano-MgO (34.9%)/Fe-Cr-Ni composites is the best of the four kinds of porous composites.

Keywords

• <i>in-situ</i> synthesis
• ceramic particle reinforced metal matrix composites
• bending strength
• oxidation resistance