Strengthening effect of twin boundaries in bcc crystal evaluated through a micro-bending test

2011 ◽  
Vol 1297 ◽  
Author(s):  
Yuki Karasawa ◽  
Tso-Fu Mark Chang ◽  
Akinobu Shibata ◽  
Masato Sone
Keyword(s):  
Shear Stress ◽  
Type Specimen ◽  
Bending Test ◽  
Displacement Curve ◽  
Strengthening Effect ◽  
Body Centered Cubic ◽  
Twin Boundaries ◽  
Bending Deformation ◽  
Nano Scale ◽  
Critical Resolved Shear Stress

ABSTRACTIn the present study, the strengthening effect of nano-scale twins in body-centered cubic (bcc) crystal was evaluated using micro-sized cantilever type specimen which contained the nanotwinned region (midrib) in ferrous lenticular martensite. The SEM observations of the micro-sized specimen after bending deformation indicated that midrib can act as barriers against dislocations, resulting in slip localization and non-localization across midrib. The load-displacement curve obtained by bending test showed that twin boundaries significantly enhance the critical resolved shear stress of bcc.

ORIENTATION DEPENDENCE OF YIELD IN BODY-CENTERED CUBIC METALS

1967 ◽  
Vol 45 (2) ◽  
pp. 1091-1099 ◽  
Author(s):  
D. Hull ◽  
J. F. Byron ◽  
F. W. Noble
Keyword(s):  
Shear Stress ◽  
Deformation Behavior ◽  
Orientation Dependence ◽  
Compressive Deformation ◽  
Slip Systems ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
The Asymmetry ◽  
Critical Resolved Shear Stress ◽  
And Tungsten

Recent observations relating to the critical resolved shear stress for slip in tantalum and tungsten are reported. The results of tensile and compressive deformation are discussed in terms of the operative slip systems and the possible asymmetry of {112} [Formula: see text] slip. It is concluded that the asymmetry hypothesis is unable to account satisfactorily for anomalies in the deformation behavior of these materials.

scholarly journals Interaction of Migrating Twin Boundaries with Obstacles in Magnesium

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 154
Author(s):  
Andriy Ostapovets ◽  
Konstantin Kushnir ◽  
Kristián Máthis ◽  
Filip Šiška
Keyword(s):  
Shear Stress ◽  
Finite Elements ◽  
Twin Boundary ◽  
Computer Simulations ◽  
Bulk Material ◽  
Twin Boundaries ◽  
Twin Growth ◽  
Critical Resolved Shear Stress

Interaction of migrating {101¯2} twin boundary with obstacles was analyzed by atomistic and finite elements computer simulations of magnesium. Two types of obstacles were considered: one is a non-shearable obstacle and another one is the void inside bulk material. It is shown that both types of obstacles inhibit twin growth and increased stress is necessary to engulf the obstacle in both cases. However, the increase of critical resolved shear stress is higher for the passage of the twin boundary through raw of voids than for interaction with non-shearable obstacles.

scholarly journals Enhanced lattice distortion, yield strength, critical resolved shear stress, and improving mechanical properties of transition-metals doped CrCoNi medium entropy alloy

RSC Advances ◽  
2021 ◽  
Vol 11 (38) ◽  
pp. 23719-23724
Author(s):  
Md. Lokman Ali
Keyword(s):  
Mechanical Properties ◽  
Shear Stress ◽  
Transition Metals ◽  
Yield Strength ◽  
Lattice Distortion ◽  
Critical Resolved Shear Stress

The effect of transition-metals (TM) addition on the mechanical properties of CrCoNi medium entropy alloys (MEAs) was investigated.

On the Critical Resolved Shear Stress and its Importance in the Fatigue Performance of Steels and other Metals with Different Crystallographic Structures

2022 ◽  
pp. 37-65
Author(s):  
M. Mlikota
Keyword(s):  
Shear Stress ◽  
Fatigue Life ◽  
Fatigue Limit ◽  
High Fatigue ◽  
Steel Aisi ◽  
Crystallographic Structures ◽  
Face Centered ◽  
Set Up ◽  
Number Of Cycles ◽  
Critical Resolved Shear Stress

This study deals with the numerical estimation of the fatigue life represented in the form of strength-life (S-N, or Wöhler) curves of metals with different crystallographic structures, namely body-centered cubic (BCC) and face-centered cubic (FCC). Their life curves are determined by analyzing the initiation of a short crack under the influence of microstructure and subsequent growth of the long crack, respectively. Micro-models containing microstructures of the materials are set up by using the finite element method (FEM) and are applied in combination with the Tanaka-Mura (TM) equation in order to estimate the number of cycles required for the crack initiation. The long crack growth analysis is conducted using the Paris law. The study shows that the crystallographic structure is not the predominant factor that determines the shape and position of the fatigue life curve in the S-N diagram, but it is rather the material parameter known as the critical resolved shear stress (CRSS). Even though it is an FCC material, the investigated austenitic stainless steel AISI 304 shows an untypically high fatigue limit (208 MPa), which is higher than the fatigue limit of the BCC vanadium-based micro-alloyed forging steel AISI 1141 (152 MPa).

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