GH3625合金管材短流程制备过程中的晶界特征分布和织构演变

Grain Boundary Character Distribution and Texture Evolution in Short-flow Manufacture process of GH3625 Alloy Tubes

摘要:

采用EBSD和OIM技术研究了GH3625合金管材短流程制备过程中(热挤压、固溶处理、冷轧及退火处理)的晶界特征分布和织构演变规律,进一步通过分析Schmid因子和Taylor因子研究合金管材的冷热塑性变形能力。结果表明,GH3625合金管材的晶界特征分布主要是以退火孪晶相关的Σ3_ⁿ晶界优化的,而不是形变孪晶；GH3625合金管材在热挤压/冷轧变形过程中主要形成Brass织构{110}<112>和Fiber织构<111>//RD,而在固溶/退火处理过程中主要形成{110}<110>织构和Brass-R织构{111}<112>；GH3625合金管材在热挤压变形时优先在挤压方向(RD)发生塑性变形,而在冷轧变形时优先在垂直于轧向的方向发生塑性变形；同时,对比热挤压和冷轧变形过程中GH3625合金管材平均的Schmid因子值m_s和Taylor因子值M_T发现冷轧变形比热挤压变形的塑性变形能力差,需要更高的形变功。

Abstract:

In this work, the grain boundary characteristics distribution and texture evolution of GH3625 alloy tubes during short-flow manufacture process (hot extrusion, solution treatment, cold rolling and annealing treatment) were investigated by electron backscatter diffraction (EBSD) and orientation imaging microscopy (OIM) technique. And the cold and hot plastic deformability of alloy tubes via analyzing the Schmid factor and Taylor factor were further studied. The results show that the grain boundary character distribution in the short-flow manufacture process of GH3625 alloy tubes is optimized through annealing twins related to Σ3_ⁿ grain boundaries rather than deformation twins. The Brass texture {110}<112> and fiber texture <111>//RD is generated in the hot extrusion/cold rolling deformation process of the alloy tubes, while the {110}<110> texture and Brass-R texture {111}<112> appear during solution/annealing treatment. GH3625 alloy tubes preferentially plastic deformation in the extrusion direction (RD) during hot extrusion, while plastic deformation occurs in the direction perpendicular to the rolling direction during cold rolling. At the same time, comparing the average Schmid factor value m_s and Taylor factor value M_T of GH3625 alloy tubes during hot extrusion and cold rolling deformation, it is found that the plastic deformability of cold rolling is worse than hot extrusion, and higher deformation work is needed.