【摘要】 采用多道次ECAP温变形实现了高碳珠光体钢组织的超细化,利用透射电镜(TEM)和原子力显微镜(AFM)观察了变形前后珠光体的演变情况,并用纳米压痕技术表征了铁素体相的纳米力学性能。结果表明:经历大应变温变形之后,制备出了晶粒尺度均在亚微米量级的超微细复相组织(铁素体+粒状渗碳体),珠光体的组织形态发生由二维层片状向三维等轴状的转变;等轴状亚微米级铁素体相的纳米压痕硬度和Young’s模量分别为4.4 GPa和200 GPa,都略高于原始珠光体组织,当压痕深度超过100 nm之后,纳米压痕硬度呈现出明显的基底效应,而Young’s模量则趋于一致,对基底效应不敏感。更多还原

【Abstract】 Ultrafine pearlite microstructure of a high carbon steel was obtained by warm equal channel angular pressing(ECAP),in which development of pearlite morphorogy was investigated by transmission electron microscopy(TEM) and atomic force microscopy(AFM) and properties of ferrite was characterized by nanoindentation method.The results show that the submicron duplex microstructure(ferrite(α)+cementite(θ)) is obtained in the high carbon steel,and the cementite morphology changes from lamellar shape to equiaxed grains after severe warm deformation.The nanoindentation hardness and Young’s modulus of equiaxed submicron ferrite of the steel after ECAP are 4.4 GPa and 200 GPa,respectively,which are higher than those of the original pearlite.While the nanoindentation depth is over 100 nm,nanoindentation hardness exhibits obvious substrate-effect,but the Young’s modulus is not sensitive to the substrate-effect.更多还原