Activities of Non-Basal Slips in Deformation of Magnesium Alloy Single and Poly Crystals

2018 ◽  
Vol 941 ◽  
pp. 1242-1247
Author(s):  
Shinji Ando ◽  
Hiroaki Rikihisa ◽  
Masayuki Tsushida ◽  
Hiromoto Kitahara

In this study, to investigate effects of yttrium and other elements for non-basal slips, magnesium alloy single crystals were stretched parallel to basal plane in various temperatures, and polycrystalline magnesium alloys were also tested to estimate contribution of non-basal slips to their tensile deformation behaviour. In pure magnesium single crystals, second order pyramidal (c+a) slip (SPCS) was observed at 298K. Above room temperature, first order pyramidal (c+a) slip (FPCS) was active. In the Mg - (0.6-0.9) Y alloy single crystals, FPCS was observed at 77K to 298K, while yield stress of the Mg-Y alloy single crystals was higher than that of pure magnesium. In tensile test of polycrystalline specimen, slips lines of non-basal slip systems such as SPCS, FPCS and prismatic slip were observed even at yielding in addition to basal slip lines. Among the non-basal slips, activities of FPCS and prismatic slips were increased with increasing strain in Mg - Y alloy polycrystals. Our study suggested that active non-basal slip system in tension parallel to basal plane is (c+a) pyramidal slip and enhanced ductility of magnesium - yttrium alloy would be caused from increased activity of FPCS by yttrium addition.

2014 ◽  
Vol 783-786 ◽  
pp. 341-345 ◽  
Author(s):  
Shinji Ando ◽  
Atsushi Kodera ◽  
Kazuki Fukushima ◽  
Masayuki Tsushida ◽  
Hiromoto Kitahara

According to von-Mises criterion, five kinds of independent slip systems are required for uniform deformation, so it is necessary to activate non-basal slip systems to show good ductility. However, it has not become clear the effect of Zn or Al for non-basal slip systems yet. To investigate deformation behavior of magnesium crystal by non-basal slip and alloying effect for the non-basal slip, pure magnesium and Mg-Al-Zn single crystals were stretched in the [110] direction. While {112}<23> second order pyramidal slip was activated at room temperature in pure magnesium, {101}<23> first order pyramidal slip became active slip at higher temperature. In Mg-Al-Zn alloy single crystal, {101} twin also activated by adding aluminum. These results indicate that active non-basal slip systems and twin in magnesium strongly depend on deformation temperature and alloying elements.


2014 ◽  
Vol 18 (sup4) ◽  
pp. S4-148-S4-151
Author(s):  
Y.-T. Liu ◽  
J.-X. Zhou ◽  
C.-W. Zhan ◽  
S.-Q. Tang ◽  
Y.-S. Yang

2021 ◽  
Vol 1016 ◽  
pp. 516-521
Author(s):  
Tomohiro Hanada ◽  
Masayuki Tsushida ◽  
Hiromoto Kitahara ◽  
Shinji Ando

Tensile tests of Mg-Y single crystals with different yttrium concentrations: 0.07 and 0.3 at.% were carried out to investigate effects of yttrium on pyramidal <c+a> slip system. In Mg-0.07at%Y alloy single crystals, {11 2}< 23> second order pyramidal <c+a> slip was activated and yield stress increased, compared to pure Mg single crystals. On other hand, in Mg-0.3at%Y alloy single crystals, {10 1}< 23> first order pyramidal <c+a> slip was activated and yield stress increased, compared to Mg-0.07at%Y alloy single crystals. The change in slip system by yttrium addition would be caused by increasing critical resolved shear stress (CRSS) for second order pyramidal slip.


2020 ◽  
Vol 35 ◽  
pp. 1-8
Author(s):  
Hua Qian Ang

The tensile deformation behaviour of magnesium alloy AE44 (Mg-4Al-4RE) under strain rates ranging from 10-6 to 10-1 s-1 has been investigated. Present study shows that the deformation mode begins with the activation of elastic (Stage 1), followed by <a> basal slip and twinning (Stage 2), <a> prismatic slip (Stage 3) and finally to <c+a> pyramidal slip (Stage 4). The commencement of these deformation mechanisms results in four distinct stages of strain hardening in the stress-strain curve. In this work, the four stages of deformation behaviour are modelled, and an empirical equation is proposed to predict the entire stress-strain curve. Overall, the model predictions are in good agreement with the experimental data. This study on the decomposition of stress-strain curve into four stages provides insights into the contribution of individual deformation mechanism to the overall deformation behaviour and opens a new way to assess mechanical properties of die-cast magnesium alloys.


Author(s):  
Yuzhou Du ◽  
Mingyi Zheng ◽  
Yanfeng Ge ◽  
Bailing Jiang

Abstract The present study investigated anisotropy in tensile behavior of an extruded Mg-4.50Zn-1.13Ca (wt.%) alloy through tensile testing along different tilt angles relative to the extrusion direction. Results showed that the as-extruded Mg-4.50Zn-1.13Ca (wt.%) alloy exhibited anisotropy in tensile behavior due to the formation of basal texture. Basal slip, prismatic slip and tensile twinning were the dominant deformation modes depending on the tensile direction. Prismatic slip was the dominant deformation mode for samples with small tilt angle (θ = 0° and 22.5°). Basal slip was activated when the tilt angle was increased, which also resulted in the decrease of yield strength. Tensile twinning was responsible for the yielding of the samples with high tilt angles (θ = 67.5° and 90°). The ductility was significantly reduced at high tilt angle, which was mainly attributed to the appearance of tensile twinning during tensile deformation.


1957 ◽  
Vol 35 (1) ◽  
pp. 38-47 ◽  
Author(s):  
G. B. Craig ◽  
B. Chalmers

The tensile plastic deformation of single-crystal and tricrystal specimens of zinc was investigated by analysis of the external change in shape of the specimens, and of the changes in X-ray diffraction patterns. It was demonstrated that the single crystals deformed by slip on the basal plane, but pyramidal as well as basal slip occurred in specimens containing grain boundaries.


2014 ◽  
Vol 598 ◽  
pp. 98-101
Author(s):  
Gang Wan ◽  
Bao Lin Wu

the hot extruded AZ31 magnesium alloy which has basal texture was impacted along different direction and different fracture mode appeared. Under different impacted direction, the basal slip, prismatic slip, pyramidal slip, compression twin and tension twin have different critical resolved shearing stress (CRSS) and Schmid factor. Then different deformation modes were activated and resulted to different fracture modes.


2007 ◽  
Vol 345-346 ◽  
pp. 101-104 ◽  
Author(s):  
Shinji Ando ◽  
Naoharu Harada ◽  
Masayuki Tsushida ◽  
Hiromoto Kitahara ◽  
Hideki Tonda

It is important to research activation of the slip systems in magnesium crystals to understand deformation behavior of magnesium. In this study, pure magnesium, Mg-7.0at%Li and Mg-0.1at%Zn single crystals were stretched in the [11-20] direction in the range of 77K to 573K to investigate the deformation behavior by non-basal slip. The active slip system was investigated by the observation of slip bands, etch pit bands and dislocations by TEM. {11-22} <-1-123> second order pyramidal slip is activated in all magnesium and magnesium alloy single crystals, and its yield stress shows anomalous temperature dependence in the range from 77K to 293K, however, the yields stress decreased rapidly with increasing temperature above 293K. The yield stress due to the pyramidal slip in Mg-Li and Mg-Zn alloy were lower than that of pure magnesium about 20MPa whereas the stress of Mg-Zn at 77K was about two times higher than pure magnesium.


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