Low-Cycle Fatigue Behavior of an Al-Mg-Si Alloy with and without a Small Addition of Sc

Chihiro Watanabe; Ryoichi Monzen

doi:10.4028/www.scientific.net/MSF.654-656.938

Paper Titles

Effect of Applied Stress on Nucleation and Growth of Precipitates in a Cu-Be-Co Alloy
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Dispersoid Phases in 6xxx Series Aluminium Alloys
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TEM Observation of Metastable Phases in Aged Al-Mg-Ge Alloys
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Influence of Solution Treatment on Microstructure and Quench Cracking in a Water-Quenched Aluminium Alloy 7150
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Low-Cycle Fatigue Behavior of an Al-Mg-Si Alloy with and without a Small Addition of Sc
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Solute Segregation at Σ11(113)[110] Grain Boundary and Effect of the Segregation on Grain Boundary Cohesion in Aluminum from First Principles
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Understanding the Directional Dependence of Intergranular Corrosion in Aluminium Alloys
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Experimental Investigation of the Dynamic Behavior of Aluminum Foams
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Alloy Design for Enhancing the Fracture Resistance of Heat Treated High Pressure Die-Castings
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HomeMaterials Science ForumMaterials Science Forum Vols. 654-656Low-Cycle Fatigue Behavior of an Al-Mg-Si Alloy...

Low-Cycle Fatigue Behavior of an Al-Mg-Si Alloy with and without a Small Addition of Sc

Abstract:

Low-cycle fatigue behavior of a wrought Al-0.8wt%Mg-0.7wt%Si alloy with and without 0.27wt%Sc has been investigated at room temperature under constant plastic-strain amplitudes. After peak-aging treatments, both the alloys had fine lath-shaped β' precipitates. In the Sc-containing alloy, spherical Al3Sc precipitates of about 11 nm in diameter were co-existed. The alloy with Sc exhibited cyclic hardening to saturation, while the alloy without Sc showed clear cyclic softening after initial hardening. Transmission electron microscopy observation revealed that slip band structures were developed in the Sc-free alloy. Within the slip bands, shearing of the β' precipitates by moving dislocations was often observed. The cyclic softening in the alloy without Sc can then be explained by a loss of precipitation strengthening effect through the precipitation destruction within strongly-strained slip bands. In the Sc-bearing alloy, owing to the existence of non-shearable Al3Sc precipitates, dislocations were uniformly distributed, resulting in the absence of the cyclic softening.