Tensile and compressive creep behavior of extruded Mg–10Gd–3Y–0.5Zr (wt.%) alloy
- National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 (United States)
The tensile and compressive creep behavior of an extruded Mg–10Gd–3Y–0.5Zr (wt.%) alloy was investigated at temperatures ranging from 200 °C to 300 °C and under stresses ranging from 30 MPa to 120 MPa. There existed an asymmetry in the tensile and compressive creep properties. The minimum creep rate of the alloy was slightly greater in tension than in compression. The measured values of the transient strain and initial creep rate in compression were greater than those in tension. The creep stress exponent was approximately 2.5 at low temperatures (T < 250 °C) and 3.4 at higher temperatures both in tension and in compression. The compression creep activation energy at low temperatures and high temperatures was 83.4 and 184.3 kJ/mol respectively, while one activation energy (184 kJ/mol) represented the tensile–creep behavior over the temperature range examined. Dislocation creep was suggested to be the main mechanism in tensile creep and in the high-temperature regime in compressive creep, while grain boundary sliding was suggested to dominate in the low-temperature regime in compressive creep. Precipitate free zones were observed near grain boundaries perpendicular to the loading direction in tension and parallel to the loading direction in compression. Electron backscattered diffraction analysis revealed that the texture changed slightly during creep. Non-basal slip was suggested to contribute to the deformation after basal slip was introduced. In the tensile–creep ruptured specimens, intergranular cracks were mainly observed at general high-angle boundaries. - Highlights: • Creep behavior of an extruded Mg–RE alloy was characterized by EBSD. • T5 aging treatment enhanced the tension–compression creep asymmetry. • The grains grew slightly during tensile creep, but not for compressive creep. • Precipitate free zones (PFZs) were observed at specific grain boundaries. • Intergranular fracture was dominant and cracks mainly originated at GHABs.
- OSTI ID:
- 22476003
- Journal Information:
- Materials Characterization, Vol. 99; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACTIVATION ENERGY
ASYMMETRY
BACKSCATTERING
COMPRESSION
CRACKS
CREEP
DEFORMATION
DISLOCATIONS
ELECTRON DIFFRACTION
GADOLINIUM COMPOUNDS
GRAIN BOUNDARIES
MAGNESIUM COMPOUNDS
PRECIPITATION
PRESSURE RANGE MEGA PA
QUATERNARY ALLOY SYSTEMS
RUPTURES
STRESSES
TRANSIENTS
YTTRIUM COMPOUNDS
ZIRCONIUM COMPOUNDS