Rolling Anisotropy of Ni3Al Single Crystals

1986 ◽  
Vol 81 ◽  
Author(s):  
Katsuya Watanabe ◽  
Masaaki Fukuchi

AbstractThe rolling anisotropy of Ni3Al single crystals was studied. A single crystal sheet in the (011) plane showed remarkable anisotropy. Rolling the sheet in the [100] direction was simple but was almost impossible in the [011] direction. Substantial anisotropy was not observed in the (111) and (001) sheets. The texture of the rolled (011) and (111) sheets were {011}<011>. It is concluded that the rolling anisotropy of single crystal sheets is determined by the presence of active slip system related to compressive strain normal to the sheet plane, and tensile strain parallel to the rolling direction.

Author(s):  
G. A. Stone ◽  
G. Thomas

A single crystal stressed in the [3]𝛄 direction at 185°K was transformed to 5% 𝛂 martensite and 2% Ɛ martensite by volume. The austenite slip system of maximum shear stress is the (11)𝛄 [01)𝛄. Fig. 1 shows a two surface study using the electron and optical microscopes. The a martensite is confined between £martensite plates with the (0001)Ɛ ∥ (11)𝛄. The size of the acicular martensite crystals is controlled by the spacing of the £ martensite plates. These £ martensite plates are seen in Fig. 1A as dark vertical bands. The axes of the acicular crystals lie in the (11)𝛄 plane. The £ martensite habit plane is defined as the plane perpendicular to the (11)𝛄 containing the vector defining the crystal axis.


Author(s):  
Sergio Conti ◽  
Georg Dolzmann ◽  
Carolin Klust

We investigated the effect of spontaneous formation of microstructures on the macroscopic material behaviour in a class of models in finite single-crystal plasticity without hardening. In particular, we show that, even in the presence of a single active slip system, the formation of slip bands leads to a very soft behaviour of the sample in response to a large class of applied loads. This contrasts with results obtained under the assumption of rigid elasticity.


2001 ◽  
Vol 683 ◽  
Author(s):  
Grethe Winther ◽  
Xiaoxu Huang ◽  
Søren Fæster Nielsen ◽  
John Wert

ABSTRACTThe dislocations in the extended planar dislocation boundaries formed during deformation are generated by the active slip systems. Investigation of the boundaries is therefore a tool to obtain information on the active slip systems. Here, the orientation of the dislocation boundaries in uniaxially deformed aluminum poly- and single crystals are compared. It is found that the single crystal boundary planes are consistent with those found in polycrystals, indicating that the active slip systems in single and polycrystals are the same. However, boundaries are closer to the slip planes in the single crystals. This is taken as an indication that the secondary slip systems are more active in the polycrystal. The orientation of the boundary plane varies with the crystal orientation in a way that is consistent with activation of the five most stressed slip systems.


1996 ◽  
Vol 460 ◽  
Author(s):  
A. Bartels ◽  
H. Clemens ◽  
C. Hartig ◽  
H. Mecking

ABSTRACTAt room temperature sheets of γ-TiAl exhibit a higher yield stress in the rolling direction than in the transverse direction. Around 700°C the opposite behavior is observed. The texture mainly consists of a modified cube component. The tetragonal c-axis (001) is aligned in the sheet plane transversely to the rolling direction. Taken into account this special texture and the single crystal yield surface of γ-TiAl we conclude that around 700°C the CRSS of super-dislocations is higher than the CRSS of ordinary dislocations. At RT the relation changes to the opposite.


1994 ◽  
Vol 357 ◽  
Author(s):  
X. J. Ning ◽  
P. Pirouz

AbstractWhen a 6H-SiC single crystal is deformed under indentation or uniaxial compression in orientations not favorable for the activation of the 1/3[1120](0001) easy glide system, the secondary slip system is activated. Additionally, for low- temperature deformations, “kinks” and/or micro-cracks form in the crystal. In this paper, experimental results on relatively lowtemperature compression and indentation tests of single crystal 6H-SiC, and the microstructure of the deformed crystals, are presented. Based on the results, the secondary slip system in 6HSiC has been determined to be 1/3[1120](1100), which may actually be a combination of alternate glide of 1/3[1120] dislocations on the (1102) and (1102) planes. Further, dislocation mechanisms for the nucleation of prism-plane and basal-plane cracks, and for the process of kinking, in deformed 6H-SiC are proposed.


2021 ◽  
Vol 173 ◽  
pp. 110941
Author(s):  
Ryan Sperry ◽  
Songyang Han ◽  
Zhe Chen ◽  
Samantha H. Daly ◽  
Martin A. Crimp ◽  
...  

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