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Micromechanics of Superplasticity

超塑性微观力学

基本信息

批准号：
08242105
负责人：
MURAKAMI Sumio
金额：
$ 69.18万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

The present project aims to elucidate the process of microstructural change governing superplastic deformation from micromechanics point of view, to establish a new theoretical framework for the precise description of superplastic behavior of various materials, and to investigate the possibility of developing new superplastic materials and new superplastic forming and manufacturing processes. The research results obtained during the term of the project are summarized as follows :1) The Head Investigator Murakami performed a series of tests on superplastic deformation and fracture under wide variety of combined states of stress, discussed the results from the micromechanics and continuum mechanics points of view, and thereby formulated a new mechanical model of describing the process of deformation and fracture of superplastic materials. The model made possible the simulation of the deformation process of the commercial superplastic material of Al5083 alloy.2) Investigator Aizawa develo … More ped extensively computational material models for the analysis of superplastic forming rocess, and established new methods of superplastic forming. He succeded in developing a simulation method for the superplastic forging by the use of the modified granular model and micro-macro stress analysis. He proposed methods of the superplastic injection forming and superplastic spinning. These two methods will be developed as a prototype of superplastic forming in the next generation.3) Investigator Maruyama observed the superplastic behavior and the associated deformation mechanisms of Ti-Al-Fe alloys, and formulated a superplastic constitutive equation for materials of two-phase structure. The results of tensile tests of the material showed superplastic elongation of 800 % at the temperature range of 1050K through 1200K. According to the microstructural observations, the relaxation mechanism of the concentrated stress was found to be the stress-induced phase transformation which is different from the mechanisms observed so far. A new constitutive equation was proposed based on this mechanism.4) Investigator Tokuda elucidated the macroscopic and microscopic properties of the commercial superplastic material of Al5083 alloy by performing combined load tests on the tubular specimens of the material. He discussed the superplastic deformation based on the constitutive theory of viscoplasticity and micromechanics, and proposed a constitutive model of fine-grained superplasticity for three-stage Finite Element Analysis. Less

本项目旨在从微观力学的角度阐明超塑性变形的微观组织变化过程，为精确描述各种材料的超塑性行为建立新的理论框架，并探索开发新的超塑性材料和新的超塑性成形和制造工艺的可能性。1)村上主任对各种组合应力状态下的超塑性变形和断裂进行了一系列试验，并从细观力学和连续介质力学的角度对试验结果进行了讨论，从而建立了描述超塑性材料变形和断裂过程的新的力学模型。该模型使模拟工业超塑性材料Al5083的变形过程成为可能。2)研究员Aizawa开发…为分析超塑性成形过程建立了更广泛的计算材料模型，建立了超塑性成形的新方法。他成功地利用改进的颗粒模型和微观-宏观应力分析开发了超塑性锻造的模拟方法。他提出了超塑性注射成形和超塑性旋压的方法。这两种方法将成为下一代超塑性成形的原型。3)丸山研究员观察了Ti-Al-Fe合金的超塑性行为及其相关的变形机制，并建立了两相结构材料的超塑性本构方程。拉伸试验结果表明，在1050~1200K温度范围内，该材料的超塑性伸长率为800%。根据显微组织观察，发现应力集中的松弛机制是应力诱导的相变，这与迄今观察到的机制不同。在此基础上提出了一个新的本构方程。4)研究人员德田通过对商业超塑性材料Al5083的管状试件进行联合加载试验，阐明了该材料的宏观和微观性质。他基于粘塑性本构理论和细观力学对超塑性变形进行了讨论，提出了适用于三阶段有限元分析的细晶超塑性本构模型。较少