Using High-Pressure Torsion to Achieve Superplasticity in an AZ91 Magnesium Alloy

Metals

RobertoB. Figueiredo¹  TerenceG. Langdon² 

[1] Department of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil;Materials Research Group, Department of Mechanical Engineering, University of Southampton, Southampton SO17 1BJ, UK;

关键词: creep;    high-pressure torsion;    magnesium;    superplasticity;   

DOI  :  10.3390/met10050681

来源: DOAJ

【 摘 要 】

An AZ91 magnesium alloy (Mg-9%, Al-1% Zn) was processed by high-pressure torsion (HPT) after solution-heat treatment. Tensile tests were carried out at 423, 523, and 623 K in the strain rate range of 10⁻⁵−10⁻¹ s⁻¹ to evaluate the occurrence of superplasticity. Results showed that HPT processing refined the grain structure in the alloy, and grain sizes smaller than 10 µm were retained up to 623 K. Superplastic elongations were observed at low strain rates at 423 K and at all strain rates at 523 K. An examination of the experiment data showed good agreement with the theoretical prediction for grain-boundary sliding, the rate-controlling mechanism for superplasticity. Elongations in the range of 300–400% were observed at 623 K, attributed to a combination of grain-boundary-sliding and dislocation-climb mechanisms.

【 授权许可】

Unknown