Evaluation of plastic working properties of fine grained aluminum alloy

本研究的目的是利用温热多轴交替锻造（MAF）方法来改善和评估具有过度细晶组织的材料的塑性加工性能和生产工艺，该方法是由于提高铝合金强度而引起的硬应变诱导方法之一。具有亚微米晶粒尺寸的微观结构的板材的发明能够根据温多轴交替锻造锻造和轧制的组合加工工艺获得足够的成功。* 双轴拉伸试验机作为评价细晶结构材料塑性加工的试验，并检查该机器具有足够的精度作为拉伸试验机，其规格如下：（载荷; 5 kN和行程; 120 mm，应变速率; 10^<-5>N 10 ^3，温度; 100 ℃，试样形状;十字形）。此外，还对十字形试件的最佳形状和尺寸进行了研究 关于我们 2003年 * 生产的十字形试样在高温变形下的双轴应力条件下可产生80%或更大的塑性变形。* 虽然m值在单轴应力下随着应变速率的增加而减小，但是该值在双轴应力下保持0.30或更大至1.7 X 10^<-1>s^，<-1>这是高应变速率。* 对于相同晶粒尺寸的试样，在单、双轴应力作用下，许多力学性能差异显著。在产生这种差异的退火温度673 K下，单轴和双轴应力下的n值分别为0.33和0.26。* 在单轴和双轴应力状态下，晶粒尺寸对力学性能的影响是不同的。* 在实验温度为673 K、应变速率为8.3 × 10 ~（-3）s ~（-1）的条件下<-2><-1>，在双轴应力下，当应变速率变化约60%时，在没有剪切变形的情况下，也出现了动态再结晶现象。* 在673 K温度下，在单轴应力作用下，虽然晶粒沿拉伸方向发展，孔洞在垂直于拉伸方向上产生，但变形后的晶粒形状在双轴应力作用下仍保持等轴变形状态，孔洞在任意方向产生，由于细晶材料超塑性变形的变形状态随加载应力状态而变化，在变形模拟中，有必要使用双轴应力下的加工工艺评价参数，对加工工艺条件进行推测。少

The purpose of this research is to improve and evaluate the plastic working properties and production process of material which overly has a fine grained structure using the warm multi-axial alternative forging (MAF) method which is one of some hard strain induced methods due to enhancement of the strength of aluminum alloy.2002 * The invention of board material which has microstructure with sub micrometer grain size was able to achieve sufficient success according to the combination processing process of warm multi-axial alternative forging forge and rolling. * The bi-axial tension testing machine made as an experiment for evaluation of the plastic processing of material with fine grained stricture and it checked that this machine had accuracy sufficient as tensile testing machine with specification as following : (Load ; 5 kN and Stroke ; 120mm, Strain rate ; 10^<-5>〜10^3, Temperature ; 〜600℃, Shape of specimen ; cruciform). Moreover, the optimal form and size of cruciform specimen u … More sed were determined.2003 * The produced cruciform specimens can give plastic deformation of 80% or more in conditions of bi-axial stress under high temperature deformation. * Although m value decreases with the increase in strain rate under uni-axial stress, that value maintains 0.30 or more to 1.7 x 10^<-1>s^<-1> which is high strain rate under bi-axial stress. * For same grain sized specimens, the difference of many mechanical characteristics appeared notably under uni-axial and bi-axial stress. In annealing temperature 673K in which the difference produced, n values were 0.33 and 0.26 under a uni-axial and bi-axial stress respectively. * The effect of grain size on mechanical properties is different for condition under uni-axial and bi-axial stress. * At experimental temperature 673K and strain rate 8.3 x 10^<-2>s^<-1>, the dynamic re-crystallization was checked also under bi-axial stress without shear deformation after changing about 60%. * Although a crystal grain develops in the tensile direction and voids arise perpendicularly to the tensile direction under uni-axial stress at temperature 673K,the shape of deformed grain maintains the situation of equiaxial distortion for bi-axial stress and voids produces to arbitrary directions.Since the situation of deformation changes with loading stress states in the superplasticity deformation using fine grained material, it is necessary to use the work processing evaluation parameter under bi-axial stress in the deformation simulation for work processing condition presumption. Less