The Effect of Thermomechanical Processing on the Tensile, Fatigue, and Creep Behavior of Magnesium Alloy AM60

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Metallurgical and Materials Transactions A

DOI:https://doi.org/10.1007/s11661-010-0478-x· OSTI ID:1023821

Chen, Zhe ^[1]; Huang, J ^[2]; Decker, R ^[2]; Lebeau, S ^[2]; Walker, Larry R ^[3]; Cavin, Odis Burl ^[3]; Watkins, Thomas R ^[3]; Boehlert, C. J. ^[1]

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1. Michigan State University, East Lansing
2. Thixomat, Incorporated
3. ORNL

Tensile, fatigue, fracture toughness, and creep experiments were performed on a commercially available magnesium-aluminum alloy (AM60) after three processing treatments: (1) as-THIXOMOLDED (as-molded), (2) THIXOMOLDED then thermomechanically processed (TTMP), and (3) THIXOMOLDED then TTMP then annealed (annealed). The TTMP procedure resulted in a significantly reduced grain size and a tensile yield strength greater than twice that of the as-molded material without a debit in elongation to failure ({epsilon}{sub f}). The as-molded material exhibited the lowest strength, while the annealed material exhibited an intermediate strength but the highest {epsilon}{sub f} (>1 pct). The TTMP and annealed materials exhibited fracture toughness values almost twice that of the as-molded material. The as-molded material exhibited the lowest fatigue threshold values and the lowest fatigue resistance. The annealed material exhibited the greatest fatigue resistance, and this was suggested to be related to its balance of tensile strength and ductility. The fatigue lives of each material were similar at both room temperature (RT) and 423 K (150 C). The tensile-creep behavior was evaluated for applied stresses ranging between 20 and 75 MPa and temperatures between 373 and 473 K (100 and 200 C). During both the fatigue and creep experiments, cracking preferentially occurred at grain boundaries. Overall, the results indicate that thermomechanical processing of AM60 dramatically improves the tensile, fracture toughness, and fatigue behavior, making this alloy attractive for structural applications. The reduced creep resistance after thermomechanical processing offers an opportunity for further research and development.

• Research Organization: Oak Ridge National Laboratory (ORNL); High Temperature Materials Laboratory; Shared Research Equipment Collaborative Research Center
• Sponsoring Organization: EE USDOE - Office of Energy Efficiency and Renewable Energy (EE)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1023821
• Journal Information: Metallurgical and Materials Transactions A, Journal Name: Metallurgical and Materials Transactions A Journal Issue: 5 Vol. 42A; ISSN 1073-5623
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOYS
CREEP
DUCTILITY
ELONGATION
FRACTURE PROPERTIES
GRAIN BOUNDARIES
GRAIN SIZE
MAGNESIUM ALLOYS
Mg alloy
PROCESSING
STRESSES
TENSILE PROPERTIES
YIELD STRENGTH
mechanical properties
microstructure