Mechanism of Continuous Recrystallization under Superplasticity

超塑性下连续再结晶机理

基本信息

批准号：
12650710
负责人：
YANG Xuyue
金额：
$ 2.24万
依托单位：
The University of Electro-Communications
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650710/
关键词：
continuous dynamic recrystallization superplasticity texture new grain evolution kink band misorientation grain boundary sliding aluminum and magnesium alloys 動的連続再結晶結晶粒微細化 SUPRAL100、7075アルミニウム合金

项目摘要

The research falls roughly into the following two heads.( 1 ) Continuous Recrystallization in a Superplastic Aluminum AlloyThe misorientations of subgrain boundaries evolved in the pancaked grains increase accompanied by a randomization of the initial texture, followed by a new grain development with high angle boundaries (HABs) at high strains. Increasing in the pre cold-rolled reduction results in a decrease in the flow stress and a rapid increase in total elongation. Grain boundary sliding (GBS) frequently takes place just after yielding even in the layered HABs parallel to the tensile axis. With further straining, GBS can bring about the rotation of subgrains near the HABs, leading to increase inMhe subgrain misorientation. It is concluded that nonrecrystallized and pancaked grain structure introduced by cold rolling is an important prerequisite not only for the appearance of superplasticity, but also for the dynamic evolution of new fine grains.(2) Dynamic Evolution of New Grains … More during Hot Deformation of Magnesium Alloy AZ31The flow curve shows a rapid hardening and a stress peak at relatively low strain (ε_p=0. 12), followed by a strain softening and then a steady state flow in high strain. Fine grains are evolved at original grain boundaries corrugated at around ε_p and developed rapidly during strain softening, finally leading to a roughly full evolution of equiaxial fine grains. On the other hand, kink bands are evolved at grain boundaries corrugated and also frequently in grain interiors even at around %. The misorientation of the boundaries of kink band increases rapidly during strain softening and approach a saturation value of around 43゜ in high strain. The average size of the regions fragmented by kink band is almost the same as that of new grains evolved in high strain, which scarcely changes during deformation. It is concluded therefore that new grain evolution can be controlled by a deformation-induced continuous reaction, i.e. continuous dynamic recrystallization (DRX), although many characteristics of new grain evolution process and its relation to flow behaviors are apparently similar to those in conventional, i.e. discontinuous, DRX. Less

该研究大致落入了以下两个头部。（1）在巨型铝合金中连续重结晶，在欺骗谷物中进化的亚晶边界的不良反应增加了初始质地的随机化，随后是高质量高质量的新谷物发育（HAB）的新谷物发育。前冷降低减少的增加会导致流动应力减少和总伸长率迅速增加。即使在平行于拉伸轴的分层HAB中屈服后，晶界滑动（GB）经常发生。通过进一步的紧张，GB可以在HAB附近带来亚晶粒的旋转，从而增加Inmhe亚晶粒不良方向。结论是，冷滚动引入的非重结式和胰纹理结构不仅是出现超塑性的重要先决条件，而且是新谷物的动态演变。（2）新晶粒的动态演变……在镁合金稳定下均高于峰值的峰值均高于峰值，而峰值均高于峰值，而峰值均高于峰值，而二重性均高于高度（均为峰值）。软化，然后在高应变中流动。细晶粒在原始的晶界处进化，在ε_p左右瓦楞纸，并在应变软化过程中迅速发展，最终导致了近日细晶粒的大致完全演变。另一方面，扭结条带在波纹的晶界发展，即使在百分比左右也经常在谷物内部。在应变软化过程中，扭结条带的边界的不良取向迅速增加，并且在高应变中接近饱和值约为43゜。扭结带碎片区域的平均大小几乎与高应变中的新谷物的平均大小相同，在变形过程中几乎没有变化。因此，得出结论，新的晶粒进化可以通过变形引起的连续反应，即连续的动态再结晶（DRX）来控制，尽管新晶粒进化过程的许多特征及其与流动行为的关系显然与常规的相似，即不连续的不连续性，DRX。较少的