Effects of Mg Content on the Fatigue Strength and Fracture Behavior of Al-Si-Mg Casting Alloys

Journal Article · Thu Nov 15 04:00:00 EST 2018 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-018-3688-9· OSTI ID:22863183

Wu, Ming-Ze; Zhang, Ji-Wang ^[1]; Zhang, Yan-Bin ^[2]; Wang, Hua-Qiang ^[1]

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1. Southwest Jiaotong University, State Key Laboratory of Traction Power (China)
2. Southwest Jiaotong University, School of Mechanical Engineering (China)

In order to investigate the influence of Mg content on the fatigue properties in Al-Si-Mg alloy, uniaxial tensile tests and rotating bending fatigue tests were conducted on two Al-7Si-Mg casting alloys, with different Mg contents of 0.3 and 0.6 wt.%. The fracture surfaces of the specimens were observed by scanning electron microscopy, and the fatigue crack growth process was obtained by the replica method. The results indicate that the increase in Mg content enhances the yield strength and tensile strength of the alloy, whereas it reduces its elongation. There is an obvious knee point in the S–N curves of Al-7Si-0.6Mg alloy while that of Al-7Si-0.3Mg alloy shows continuous decrease. The fatigue strength at 5 × 10{sup 5} cycles is 60 MPa for Al-7Si-0.3Mg alloy and 80 MPa for Al-7Si-0.6Mg alloy. For the two types of specimens, the fatigue failure can initiate from crystal slip and casting defects. The replica results suggest that cracks in Al-7Si-0.6Mg alloy grow more slowly than that in Al-7Si-0.3Mg alloy.

• OSTI ID: 22863183
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 11 Vol. 27; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CASTING
CRACK PROPAGATION
ELONGATION
FATIGUE
FRACTURES
MAGNESIUM COMPOUNDS
PRESSURE RANGE MEGA PA 10-100
SCANNING ELECTRON MICROSCOPY
SILICON COMPOUNDS
SURFACES
TENSILE PROPERTIES
YIELD STRENGTH