Crushing Behavior of Alumina Inclusions with Different Porosity During Hot Compression

Abstract Alumina inclusions in commercial as-cast 2.25Cr1Mo0.25V aluminum deoxidized steel exhibited a feature of porous structure. In order to investigate the crushing characteristics of alumina inclusion during hot working, a series of alumina blocks with different porosity whose properties are similar to the alumina inclusions in ingots were prepared using spark plasma sintering. The crushing behavior of alumina blocks during hot compression with quasi-static load was studied. A prediction model of compressive strength of alumina inclusions considering apparent porosity was established on basis of hyperbolic sine Arrhenius equation. A novel crushing mode diagram for alumina inclusions characterized by Z parameter was proposed. The crushing mechanism of alumina inclusions under different deformation parameters was clarified by fracture characteristics. The results showed that the hot compression process of alumina presented a typical brittle fracture, the compressive strength was more sensitive to deformation conditions at lower apparent porosity as compared with the conditions of higher apparent porosity. With the increase of Z, the crushing mode of alumina inclusions gradually changed from intergranular fracture to transgranular fracture.