初始织构对差厚板非均匀塑性变形的影响

Influence of Initial Texture on Inhomogeneous Plastic Defor-mation of Tailor Rolled Blank

摘要:

CR340轧制差厚板（TRB）在轧制过程中，其不同的厚度区形成了不同的织构，分别是薄区的{111}<01>和{141}<22>织构，过渡区的{225}<10>和{211}<01>织构，厚区的{876}<5>和{411}<01>织构。根据EBSD测试结果，建立了各厚度区的多晶体塑性有限元模型，研究了单向拉伸时各厚度区的晶粒织构对滑移系开动情况和应力应变分布的影响规律。结果表明，薄区的{111}<01>织构和厚区的{876}<5>织构有利于滑移系的开动，开动的数量分别为9和8组，这使得等厚区在变形中的应力集中弱化，具有良好的塑性变形行为。而过渡区的{225}<10>、{211}<01>织构的晶粒滑移系开动较少，开动的数量分别为6和7组，导致应力集中，其塑性变形行为较差。差厚板各厚度区织构的差异导致其塑性变形呈现明显的不均匀性，其断裂位置发生在单轴拉伸时塑性变形较差的过渡区。

Abstract:

Different textures are formed in different thickness zones of CR340 tailor rolled blank (TRB) during rolling, including {111}<01> and {141}<22> textures in the thin zone, {225}<10> and {211}<01> textures in the transition zone, and {876}<5> and {411}<01> textures in the thick zone. The polycrystalline plastic finite element model in different thickness zones was established based on the results of EBSD test to study the influence of grain structure in different thickness zones on the activation of slip system and stress-strain distribution under uniaxial tension. The results show that the {111}<01> texture of thin zone and {876} <5> texture of thick zone are conducive to slip system activation, and 8 and 9 sets of slip systems are activated, respectively, which weaken stress concentration of equal thickness zone in the deformation process, so equal thickness zone has good plastic deformation behavior. However, the grain slip system of {225}<10> and {211}<01> textures in transition zone is less activated, and the number of activation is just 6 and 7, respectively, which lead to the high stress concentration, and thus the plastic deformation behavior is poor. The TRB presents obvious non-uniformity in plastic deformation because of the difference in texture of each thickness region, and the fracture position of the TRB appears in the transition zone with poor plastic deformation during uniaxial tension.