Microstructure and Properties Study of Warm-rolled 304 Austenite Stainless Steel with High Al Content

304 austenite stainless steels with high Al content were warm-rolled and subsequently solution-treated.The effects of Al content and deformation amount on microstructure and properties were investigated.The surface appearance and composition were analyzed by means of OM,EPMA and SEM.The results show that the alloys are composed of gray austenite phase and black ferrite phase.The precipitates consist of an enriched phase containing aluminum nitride and other carbides.With the increasing of Al content,the volume fraction of ferrite increases.The yield strengths of the alloys with 1% Al under different deformation amount are 285 MPa,266 MPa and 273 MPa,respectively.Nevertheless,the yield strengths of the alloys with 1.5% Al are 350 MPa,365 MPa and 322 MPa,respectively.The fracture surfaces of the alloys are composed of large isometric dimples（5～30 μm） and smaller dimples（≤5 μm） arranged next to each other.The fracture models belong to ductile fracture.The alloys with 1% Al have higher tensile strength,while the sample with 1.5% Al has higher yield strength.The performance indicators of the samples are improved greatly,which provides important guidance for industrial production.