Metal‐Matrix Materials for High‐Temperature Applications with Liquid Aluminum

Abstract

Herein, powder metallurgically processed transformation‐induced plasticity effect (TRIP)‐steel‐matrix composites with additions of TiO2 or Al2O3–TiO2 are investigated for their potentional use as a impact pad in aluminum melting furnaces. The composites contain volume fractions of 10% or 30% ceramic particles dispersed in a CrMnNi‐steel matrix. The formation of ceramic precipitates in the steel and the interactions between the matrix and the ceramic particles during sintering influence the microstructure of the fired materials. TiO2 promotes the formation of Mn–Ti–O spinel‐type structures whereas the Al2O3–TiO2 material induces the additional formation of Ti–Mn–Al–O solid solutions but reduces the densification progress. Despite material changes, the steel matrix undergoes α'‐martensite formation during quasi‐static tensile loading at room temperature in the reference material and in the composite variants. The yield strength in the composite variant with 10 vol% TiO2 increases by 28% (constant with 10 vol% Al2O3–TiO2), whereby the ultimate tensile strength and the fracture strain are lower for all composite variants as compared to the pure steel. The yield strength of the materials after immersion test in liquid aluminum at 800 °C is +80% (10% TiO2) or +29% (10% Al2O3–TiO2) as compared to the corroded steel material.