Microstructural evolution of Mg–Al–Ca–Sr alloy during creep

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 498; no. 1; pp. 369 - 376
• Main Authors: Sato, T., Kral, M.V.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 20.12.2008; Elsevier
• Subjects: Applied sciences; Creep; Deformation; EBSD; Exact sciences and technology; Fractures; Magnesium; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Mg–Al–Ca; Texture; Deformation; Magnesium; Creep; Mg–Al–Ca; Texture; EBSD; Crystal twin; Mg-Al-Ca; Rupture; High angle grain boundary; Magnesium base alloys; Stress effects; Microstructure; Power law; Defect formation; Fracture mode; Crack initiation
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2008.08.006

To provide new insight into microstructural development during creep, sequential EBSD (electron backscatter diffraction) orientation maps were obtained from fixed surface areas at intervals in creep tests of a high-pressure die-cast Mg–8.5Al–1Ca–0.3Sr alloy. Samples were tested at 200 °C at various stress levels to achieve power-law creep behavior. In all specimens, steady-state creep was marked by the formation of tension twins. At intermediate stress levels, specimen failure was initiated by the formation of defects at boundaries with high crystallographic misorientation. However, at high stress levels, the failure mechanism was assisted by the crack formation at interdendritic boundaries with low crystallographic misorientation.