Development of High Strength Wrought Magnesium Alloy by Multidirectional Forging under Decreasing Temperature Conditions

低温多向锻造高强度变形镁合金的研制

基本信息

批准号：
15560623
负责人：
YANG Xuyue
金额：
$ 2.05万
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：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

The research falls roughly into the following two heads.(1)Strain-Induced Grain Refinement in Mg Alloy during Hot ForgingGrain refinement of a magnesium alloy AZ31 was studied in multi-directional forging(MDF) with decreasing temperature from 623K to 423K. The MDF was carried out up to cumulative strains of around 5 with changing the loading direction during decreasing temperature from pass to pass. The structural changes can be characterized by the evolution of many mutually crossing kink bands at low strains followed by increase in their number and misorientation, finally resulting in a fully developed fine-grains at high strains. MDF with decreasing temperature can accelerate the evolution of much finer grains and the improvement of plastic workability. An average grain size of 0.3 μm is formed at an accumulative strain of 4.8 and at 423K. It is concluded that grain refinement under MDF conditions occurs by a series of deformation-induced continuous reactions; that is essentially similar to continuous dynamic recrystallization(cDRX).(2)Isochronal Annealing Behaviors of Mg Alloy After Hot DeformationTemperature dependence of the average grain size (D)is categorized into three temperature regions, i.e. (a)incubation period of grain growth at<450 K, (b)rapid grain coarsening at 473-523 K, and (c)normal grain growth at T>550 K. The number of fine grains per unit area, however, is reduced remarkably even in region (a). It is concluded, therefore, that grain growth takes place continuously in the whole regions. While, deformation texture scarcely changes even after annealing at high temperatures. It is concluded that the annealing processes operating in the hot deformed magnesium alloy is mainly controlled by grain growth accompanied with recovery, that is continuous static recrystallization(cSRX).

该研究大致落入了以下两个头部。（1）在热锻造镁合金AZ31的热锻造过程中，Strein诱导的MG合金中的谷物细化是多个方向锻造（MDF）的研究，温度从623K到423K。将MDF执行至约5左右的累积菌株，并在从通道到通过的温度降低期间改变了载荷方向。结构变化的特征是，许多相互交叉的纽带在低菌株中的演变，然后增加其数量和不良方向，最终导致高应变处的完整的细粒。温度降低的MDF可以加速更细的谷物的演变和塑料可加工性的改善。平均晶粒尺寸为0.3μm，以4.8和423K的丙烯酸应力形成。结论是，在MDF条件下，通过一系列变形诱导的连续反应发生晶粒细化。这基本类似于连续动态重结晶（CDRX）。（2）在热变形晶状体依赖性（平均晶粒尺寸（d）的温度依赖性）之后，Mg合金的等初次退火行为分为三个温度区域，即（a）在<450 K，（b）450 k，（b）473-k coars pransion grention growrentive th 473-k in fust fulastion grentive growterive covertion。 K.但是，即使在区域（a）中，每单位面积的细晶粒数量也大大减少。因此，可以得出结论，谷物的生长在整个地区不断发生。同时，即使在高温下退火后，变形纹理也几乎不会变化。结论是，在热变形镁合金中运行的退火过程主要由恢复谷物生长来控制，即连续的静态重结晶（CSRX）。