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Prediction of High-temperature Creep Deformation for Precipitation Hardened Aollys

沉淀硬化Aollys高温蠕变变形的预测

基本信息

批准号：
08650809
负责人：
GOTO Shoji
金额：
$ 1.41万
依托单位：
Akita University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
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

Precipitation hardening has been considered to be an effective strengthening method not only at room temperature but also at high temperatures. Many investigations have been carried out on high temperature deformation of precipitation hardened alloy. Recently, Arzt and Rosier have proposed a model for the high temperature deformation of dispersion strengthened alloys based on an attractive interaction of particle and dislocation, In that model. the rate controlling step in the deformation process is the thermally activated detachment of a dislocation from the departure side of a particle. The dispersion particles are thermal-stable particles. However it is well known that there is Ostwald ripening in precipitation hardened alloy. The precipitates grow up at high-temperature and the dispersion parameters of the precipitates change during high-temperature deformationIn order to clarify the influence of this Ostwald ripening on high-temperature deformation in precipitation hardened alloys, this work proposed a predicting method of high-temperature deformation behavior with Ostwald ripening of precipitates for precipitation hardened alloy. The theoretical calculations were compared with the experimental results for Al-1.03 mass% Si alloy. The evaluation was carried out of the time dependence of the threshold stress, dispersion parameters of Si precipitates and stress-strain curves for Al-1.03 mass% Si alloy. The effects of temperature raging from 473K to 723K on deformation behaviors were calculated by this prediction method. The influence of Ostwald ripening of Si precipitates on high-temperature deformation behaviors was revealed in the Al-Si precipitation hardened alloy, The results were in good agreement with experimental ones.

沉淀硬化不仅在室温下而且在高温下都被认为是一种有效的强化方法。人们对沉淀硬化合金的高温变形进行了大量的研究。最近，Arzt和Rosier提出了一个基于颗粒与位错相互吸引作用的弥散强化合金高温变形模型。变形过程中的速率控制步骤是位错从颗粒的离开侧的热激活分离。分散体颗粒是热稳定颗粒。然而，沉淀硬化合金中存在奥斯特瓦尔德熟化现象是众所周知的。析出相在高温下长大，析出相的弥散参数在高温变形过程中发生变化。为了阐明析出相的这种Ostwald熟化对沉淀硬化合金高温变形的影响，本文提出了一种用析出相的Ostwald熟化预测沉淀硬化合金高温变形行为的方法。对Al-1.03%（质量分数）Si合金的实验结果与理论计算进行了比较。对Al-1.03mass % Si合金的门槛应力、Si析出相弥散参数和应力-应变曲线的时间依赖性进行了评价。利用该方法计算了473 ~ 723 K温度范围内变形行为的变化规律。揭示了Si沉淀相的Ostwald熟化对Al-Si沉淀硬化合金高温变形行为的影响，其结果与实验结果吻合较好。