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金属学报
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BSTMUF601合金高温蠕变变形机制的实验研究
孙朝阳1,石兵1,武传标1,叶乃威2,马天军3,徐文亮4,杨竞1
1. 北京科技大学
2. 宁波宝新不锈钢有限公司
3. 宝山钢铁有限公司特殊钢事业部
4.
Experimental Investigation on High Temperature Creep Deformation Mechanism of BSTMUF601 Superalloy
全文: PDF(815 KB)  
摘要: 对BSTMUF601合金在不同温度和应力条件下进行了拉伸蠕变实验,获得了该合金的高温蠕变的变形规律,基于此提出了一种新的修正θ映射法蠕变本构模型,该模型考虑了蠕变3阶段的蠕变特点,物理意义明确。模型预测结果与实验结果吻合较好,平均相对误差为1.86%,相对于没有考虑第2阶段的θ映射法模型和没有考虑第1阶段的修正θ映射法模型分别减少0.1%和6.02%,表明该模型具有较强的适用性,且不降低预测精度。对蠕变和蠕变断裂试样的位错组态和空洞演化进行了显微分析,结果表明:稳态蠕变阶段蠕变应力指数都接近5,合金主要通过位错攀移越过 相的方式变形,并未观察到层错和微孪晶存在于 相或基体中,蠕变变形机制主要是位错攀移;空洞在晶界上形核,长大连接形成裂纹,在应力集中作用下,裂纹沿晶界扩展,最终导致断裂,蠕变断裂机制主要是晶界断裂。
Abstract:Creep tests of BSTMUF601 superalloy for elevated temperature have been carried out under different temperature and stress. The creep deformation characteristic of BSTMUF601 superalloy was investigated based on the creep curves. And then, a creep constitutive model for elevated temperature was proposed by introducing a modified θ projection method, which contains three stages of creep. The predicted results by using the model are in good agreement with the experimental results. The average relative error of the model fitted is 1.86%. Compared with the model ignored the second stage of creep and the model ignored the first stage of creep, the average relative error was reduced 0.1% and 6.02% respectively. It is indicated that the model will be a wider range of application whereas the prediction precision is not reduced. Dislocation structure and its distribution for creep specimens and void evolution for creep rupture specimens have been carried by analyzing the microscopic structure. The results show that: the creep stress index was close to 5 during the steady-state creep stage for different temperatures. The dislocation climb mechanism controlled the creep deformation process. There was no stacking fault or microtwin observed in phase or matrix. Cracks originate from the cavities at grain boundary and along the boundary, which led to fracture. Grain boundary fracture is the main creep rupture mechanism.
收稿日期: 2014-06-03     
基金资助:国家自然科学基金钢铁联合基金重点项目;国家自然科学基金青年基金项目
通讯作者: 孙朝阳   
Corresponding author: Chao-Yang SUN   

引用本文:

孙朝阳 石兵 武传标 叶乃威 马天军 徐文亮 杨竞. BSTMUF601合金高温蠕变变形机制的实验研究[J]. 金属学报, 10.11900/0412.1961.2014.00293.

链接本文:

http://www.ams.org.cn/CN/Y0/V0/I0/0

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