Tensile Deformation Behavior of Magnesium Single Crystals with Different Yttrium Concentrations

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.

2021 ◽  
Vol 1016 ◽  
pp. 1443-1447
Author(s):  
Tubasa Suzuki ◽  
Masaki Tanaka ◽  
Tatsuya Morikawa ◽  
Yelm Okuyama ◽  
Jun Fujise ◽  
...  

Czochralski silicon single crystals were deformed in tensile tests along the direction at between 1173 K and 1373. Yield point phenomenon were observed in the specimens deformed at below 1273 K while continues yield was observed in the specimens deformed at above 1323 K. It is due to the effect of dislocation starvation in the used crystals. Work-hardening rates in stage II were consistent with those reported in fcc crystals such as copper. The onset of stage II was found to be active before the Schmid factor of the second slip system becomes larger than that of the primary slip system. Electron backscattered diffraction images indicated clear kink bands near grips and in the parallel portion. The kink bands were formed at the middle of stage I, which suggest that the formation of kink bands is a trigger of stage II.


1990 ◽  
Vol 186 ◽  
Author(s):  
Y. Minonishi

AbstractDeformation characteristics of Ti3A1 single crystals has been examined as a function of orientation and temperature. This paper mainly describes the result of compression along the c axis. In this orientation, the yield stress increases from 300 to 1100K, decreasing rapidly thereafter. The slip system activated are {1121}<1126> and dislocations observed are nearly of edge character. The anomaly is discussed in comparison with the behavior of other intermetallics and pure metals. An important role this pyramidal slip plays in polycrystalline ductility of Ti3Al is shown in the light of the briefly described results of the prism slip.


Single-crystal test specimens of van Arkel titanium were obtained by a modification of the strain anneal technique.The modes of slip have been identified as (101̄0) [112̄0],(101̄1) [112̄0], and (0001) [112̄0]. It has been shown that not only does the interstitial impurity affect the magnitude of the critical resolved shear stress but also the relative values for the three slip systems. (101̄0) is the principal slip system and is favoured by increasing purity. A possible mechanism for the role of oxygen and nitrogen in this effect is put forward wherein it is shown that the interstitial sites occupied are such that interstitial elements render slip more difficult on two of the three slip planes in titanium.


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.


1967 ◽  
Vol 2 (4) ◽  
pp. 201-207 ◽  
Author(s):  
K.H. Adams ◽  
R.C. Blish ◽  
T. Vreeland

1993 ◽  
Vol 319 ◽  
Author(s):  
M. Aoshima ◽  
T. Kusube ◽  
J. Ida ◽  
Masao Doyama

AbstractSmall single crystals of titanium with and without stacking faults have been pulled by use of the molecular dynamics method. The tensile axis was [0001] and the stacking fault was introduced on (0001) pianes. The yield stress was higher in the crystal with stacking faults. The deformation was complicated in the crystal with stacking fault. Dislocations were created near the tip of a crack and moved on (1122).


2008 ◽  
Vol 1128 ◽  
Author(s):  
Katsushi Tanaka ◽  
Wang Chen ◽  
Kyosuke Kishida ◽  
Norihiko L. Okamoto ◽  
Haruyuki Inui

AbstractCompressive deformations of L10-ordered single crystals of FePd have been investigated from room temperature to 873 K. The critical resolved shear stress for superlattice dislocations is hard to determine resulting from buckling that occurs after a small amount of conventional plastic deformation. The CRSS for superlattice dislocations determined from yield stress is significantly larger than that of ordinary dislocations. The CRSS for octahedral glide of ordinary and superlattice dislocations are virtually independent of the temperature, and the positive temperature dependence of the yield stress is not observed for both, ordinary and superlattice dislocations, by the present experiments.


2017 ◽  
Vol 62 (2) ◽  
pp. 1335-1340
Author(s):  
Y.-K. Kim ◽  
J.-H. Kim ◽  
J.-H. Gwon ◽  
K.-A. Lee

Abstract This study attempted to manufacture an ODS alloy by combining multiple milling processes in mechanical alloying stage to achieve high strength and fracture elongation. The complex milling process of this study conducted planetary ball milling, cryogenic ball milling and drum ball milling in sequential order, and then the microstructure and tensile deformation behavior were investigated after additional heat treatment. The oxide particles distributed within the microstructure were fine oxide particles of 5~20 nm and coarse oxide particles of 100~200 nm, and the oxide particles were confirmed to be composed of Cr, Ti, Y and O. Results of tensile tests at room temperature measured yield strength, tensile strength and elongation as 1320 MPa, 2245 MPa and 4.2%, respectively, before heat treatment, and 1161 MPa, 2020 MPa and 5.5% after heat treatment. This results indicate that the ODS alloy of this study gained very high strengths compared to other known ODS alloys, allowing greater plastic zones.


1992 ◽  
Vol 291 ◽  
Author(s):  
Masao Doyama

ABSTRACTThe molecular dynamics method was used to simulate the plastic deformation of small copper single crystals. Dislocations were created near the tips of cracks. A very sharp yield stress was found.


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