【摘要】 对热轧和球化退火两种状态的同一种中碳低合金结构钢冷变形前后的组织结构进行了透射电子显微镜观察。结果表明 :层片状共析渗碳体与铁素体基体具有 (10 1) α- Fe∥ (0 11) Fe3C,(12 1) α- F e∥ (10 0 ) F e3C的平行位向关系。冷变形过程中 ,当渗碳体层片方向与剪应力方向呈近 4 5°或 90°时 ,层片状渗碳体分别具有流变、扭折、剪切等变形特征 ;粒状渗碳体对铁素体基体的变形有阻碍作用且形变产生的位错以 Orowan机制绕过粒状渗碳体 ,因而材料具有较好的韧性。更多还原

【Abstract】 The microstructures of hot rolled or spheroidal annealled and then cold drawn medium carbon alloy steel were observed by means of TEM. The results showed that the α Fe matrix and the eutectoid cementite lamellae keep the crystallography relationship. During cold deformation, when the directions of the eutectoid cementite lamellae and the one of the shearing stress applied are at an angle of 45° or 90°, the cementite lamellae are contorted or sheared respectively. For the steel with the particle cementite, the dislocations produced during the deformation may detour around the particles by Orowan mechanism. Therefore, the steel displays a better toughness.更多还原