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综述了金属结构材料和功能材料基体相晶体结构、层错能、Hollomon参数lnZ对等通道转角挤压ECAP变形组织演变规律影响的研究进展,试样基体相的晶体结构对变形组织的演变起重要的影响作用。随着应变量的增大,密排六方结构金属先形成形变孪晶、再启动优先存在的但被阻塞的滑移系统;面心立方结构金属的位错滑移主导着组织演变与晶粒细化过程,先形成亚晶界,再增大组织取向差,最终形成大角度晶界。在高层错能材料中,随着Hollomon参数lnZ增大,位错运动受到抑制,驱使变形机制从位错滑移逐渐转变成形变孪晶;当Z参数减小时,在ECAP高层错能材料中会形成微尺度的剪切带。在低层错能材料中形成丰富的孪晶,极低层错能的材料形成宏观剪切带。而中等层错能材料的变形机制则取决于Z值的高低。分析了ECAP过程动态再结晶的影响因素,认为γm·ln2Z>30不宜作为ECAP过程是否发生动态再结晶的判据,ECAP过程动态再结晶的影响因素还有待进一步研究,如弄清ECAP过程温升规律、分析淬火保存ECAP变形组织将有助于研究ECAP动态再结晶。
The research progress on the influence of the crystal structure of matrix, the stacking fault energy and Hollomon parameter ECAP deformation on the deformation of ECAP was summarized. The crystal structure of the matrix was important for the evolution of the deformed microstructure The impact of the role. With the increase of strain, the close-packed hexagonal structure metal first forms deformation twin and then preemptively pre-existing but blocked slip system. The dislocation slip of face-centered cubic metal structure dominates the microstructure evolution and grain refinement The process of formation, the first formation of subgrain boundaries, and then increase the poor orientation of the organization, the final formation of large-angle grain boundaries. In higher-level dislocation materials, as the Hollomon parameter lnZ increases, the dislocation motion is suppressed, and the deformation mechanism is gradually transformed from dislocation slip to deformable twins. When the Z parameter is reduced, A micro-scale shear band is formed. The formation of abundant twins in lower-level fault energy materials, and the formation of macro-shear bands for very low-level fault energy materials. The deforming mechanism of medium-layer faulty materials depends on the value of Z. The factors affecting the dynamic recrystallization of ECAP process are analyzed. It is concluded that γm · ln2Z> 30 should not be used as a criterion for dynamic recrystallization of ECAP process. The factors affecting the dynamic recrystallization of ECAP process need to be further studied. For example, Regularity, analysis of quenched ECAP deformed tissues will help to study ECAP dynamic recrystallization.