首页|Al?1.88Mg?0.18Sc?0.084Er合金的热压缩组织演变、流动应力与本构建模

Al?1.88Mg?0.18Sc?0.084Er合金的热压缩组织演变、流动应力与本构建模

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为了研究合金热压缩行为与显微组织演变,采用连续铸挤与等通道转角挤压−连续挤压方法制备细晶Al−1.88Mg−0.18Sc−0.084Er(质量分数,％)铝合金线材并在温度为673～793 K与应变速率为0.001～10 s−1条件下研究其热压缩行为.采用光学显微镜、X射线衍射仪、透射电镜和电子背散射衍射仪对合金的显微组织进行表征;采用热压缩模拟试验机获得其流动应力.显微组织演变与流动应力曲线表明,动态回复为合金主要的软化机理;在773 K和0.001 s−1条件下发生连续动态再结晶随后动态晶粒长大;发现屈服点下降现象.提出含位错变量的双曲正弦本构方程并建立幂律本构方程.应力指数为3.262,变形激活能为154.465 kJ/mol,表明位错黏性滑移为合金主要的变形机理.
Microstructural evolution, flow stress and constitutive modeling of Al−1.88Mg−0.18Sc−0.084Er alloy during hot compression
To explore the hot compression behavior and microstructural evolution, fine-grained Al−1.88Mg−0.18Sc− 0.084Er (wt.％) aluminum alloy wires were fabricated with Castex (continuous casting−extrusion) and ECAP-Conform, and their hot compression behavior was investigated at temperatures of 673−793 K and strain rates of 0.001−10 s−1; the microstructures were characterized by optical microscope, X-ray diffractometer, transmission electron microscope, and electron backscattered diffractometer, and the flow stresses were obtained by thermal compression simulator. Microstructural evolution and flow curves reveal that dynamic recovery is the dominant softening mechanism. Continuous dynamic recrystallization followed by dynamic grain growth takes place at a temperature of 773 K and a strain rate of 0.001 s−1; the yielding drop phenomenon was discovered. Hyperbolic sine constitutive equation incorporating dislocation variables was presented, and a power law constitutive equation was established. The stress exponent is 3.262, and the activation energy for deformation is 154.465 kJ/mol, indicating that dislocation viscous glide is the dominant deformation mechanism.

Al−Mg alloyECAP-Conformhot compressionmicrostructureflow stressconstitutive equation

曹富荣、尹斌、刘斯元、石路、王顺成、温景林

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东北大学材料科学与工程学院,沈阳 110819

东北大学轻质结构材料辽宁省重点实验室,沈阳 110819

东北大学轧制与连轧自动化国家重点实验室,沈阳 110819

芜湖凯翼汽车有限公司,芜湖 241000

广东工业技术研究院材料加工与成形研究所,广州 510650

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Al−Mg合金 等通道转角挤压−连续挤压 热压缩 显微组织 流动应力 本构方程

authors are grateful for the financial support from the Key Project of the National Natural Science Foundation of China

51334006

2021

10.1016/S1003-6326(20)65478-4

中国有色金属学报(英文版)
中国有色金属学会

中国有色金属学报(英文版)

CSTPCDCSCDSCI
影响因子：1.183
ISSN：1003-6326
年,卷(期)：2021.31(1)
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