Tension-Compression Asymmetry Under Superplastic Flow in Magnesium Alloys

Watanabe, Hiroyuki; Fukusumi, Masao

doi:10.1007/s11665-014-1176-4

Cited by 13 publications

(2 citation statements)

References 30 publications

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“…The trend for these m-values is found to be similar to those obtained from the compression tests, provided in Table 1. Several studies have also reported that crystal orientation (texture) had a negligible effect on ow stress during superplastic deformation, which are observed at elevated temperature ranges and in low strain rate regimes [36][37][38] . When GBS occurs even at room temperature, the material, which had similar m-value in tension and compression testing, are assumed to show an isotropic ow stress behavior.…”

Section: Resultsmentioning

confidence: 98%

Development of Isotropic and Accordion-Like Deformable Magnesium Alloys

2017

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The possibility for reduction in tension-compression asymmetric behavior and the effect of alloying elements on room temperature compressive behavior were investigated using extruded pure magnesium, several Mg-0.3 at.%X (X = Al, Li, Mn, Y and Zn) binary alloys and the commercially AZ31 alloy. They had ne-grained structures of an average grain size of 3-5 μm, except for the AZ31 alloy. The compressive deformation behavior was in uenced by the alloying elements. The Mg-Al, Mg-Zn and Mg-Y alloys showed sigmoidal shaped stress vs. strain curves, irrespective of the strain rates, due to the contribution of deformation twinning. On the other hand, pure magnesium and those alloys added with manganese or lithium as alloying elements did not exhibit such stress vs. strain behavior. Instead of deformation twinning, they had high strain rate dependence, i.e., the m-value of more than 0.1, which indicated that grain boundary sliding played an important role in deformation during compression testing. Under such a condition, in particular for the strain rates of 10 −4-10 −5 s −1 , it is interestingly noted that these speci c materials showed isotropic tension-compression behavior. They also displayed good room temperature deformability, such as accordion-like deformation, which has never been observed in magnesium alloys.

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Section: Resultsmentioning

confidence: 98%

Development of Isotropic and Accordion-Like Deformable Magnesium Alloys

2017

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“…For reference, the flow stress under tension along extrusion direction was slightly lower than that under compression along the same direction [16]. This is probably because, in superplastic magnesium alloys, the flow stress under tension becomes lower than that under compression near the maximum strain rate within the superplastic regime [23]. Texture characterization before and after superplastic deformation.…”

Section: Methodsmentioning

confidence: 99%

Texture Change during Superplastic Deformation in Fine-Grained Magnesium Alloys

Watanabe

Uesugi

Takigawa

et al. 2016

MSF

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Texture change during superplastic deformation was examined and compared in two magnesium alloys with different chemical composition. These alloys were extruded to refine the microstructure. The pre-existing basal texture of both alloys became slightly more random within the bulk probably owing to grain boundary sliding and the accompanying grain rotation. However, the texture changes differed between tensile and compressive deformation along the extrusion (longitudinal) direction. This fact suggests that dislocation slip is important in superplastic deformation. It was concluded that dislocation slip acts primarily as an accommodation mechanism for grain boundary sliding.

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