Evaluation of the relationship between the effective strain and the springback behavior during the deformation of metallic glass ribbons

2014 ◽  
Vol 105 (6) ◽  
pp. 061906 ◽  
Author(s):  
M. H. Lee ◽  
E. S. Park ◽  
R. T. Ott ◽  
B. S. Kim ◽  
J. Eckert
Keyword(s):  
Metallic Glass ◽  
Effective Strain ◽  
The Relationship ◽  
Springback Behavior

Estimation of Strain-Hardness Correlation in Cold-Forged Austenitic Stainless Steel

2014 ◽  
Vol 622-623 ◽  
pp. 179-185 ◽  
Author(s):  
Piotr Skubisz ◽  
Maciej Rumiński ◽  
Łukasz Lisiecki
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Hardening ◽  
Effective Strain ◽  
Cold Deformation ◽  
Metal Flow ◽  
Fem Simulation ◽  
Large Head ◽  
The Relationship

The paper presents selected aspects of analysis cold micro-forging process of a screw made of austenitic stainless steel, concerning relation between strain and hardness. Strain hardening character of a material in consecutive forming operations was analyzed experimentally by the measurement of hardness distribution made on longitudinal axial sections of screws. The relationship between hardness and effective strain (hardness curve) was determined, which made it possible to obtain strain distributions in different regions of a material subjected to cold deformation on the basis of strain distribution numerically estimated with FEM simulation performed using QForm2D/3D commercial software. Conclusions were formulated concerning strain inhomogeneity and strain-hardening intensity with respect to the correlation between strain and hardness. It was also concluded, that nonuniformity of hardening rate in a bulk can lead to local variations in flow stress and eventually, to occurrence of the metal flow related defects, which was illustrated with a case study of cold heading of self-tapping screw of AISI 304Cu stainless steel, with large head diameter to shank diameter ratio. In order to validate the obtained results, the same method was used for analysis of hardness development in steel 19MnB4.

scholarly journals Relationship between the Surface Roughness of Biodegradable Mg-Based Bulk Metallic Glass and the Osteogenetic Ability of MG63 Osteoblast-Like Cells

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1188 ◽  
Author(s):  
Pei-Chun Wong ◽  
Sin-Mao Song ◽  
Pei-Hua Tsai ◽  
Yi-Yuan Nien ◽  
Jason Shian-Ching Jang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Orthopedic Implants ◽  
Critical Issue ◽  
Degradation Behavior ◽  
Adhesion Ability ◽  
Mineral Deposition ◽  
First Contact ◽  
The Relationship

Mg-based bulk metallic glass materials have been investigated for their large potential for application in orthopedic implants due to their biocompatibility, low degradation rate, and osteogenetic ability. As an orthopedic implant, initial cell adhesion has been a critical issue for subsequent osteogenesis and bone formation because the first contact between cells and the implant occurs upon the implants surface. Here, we aimed to create Mg-based bulk metallic glass samples with three different surface roughness attributes in order to understand the degradation behavior of Mg-based bulk metallic glass and the adhesion ability and osteogenetic ability of the contact cells. It was found that the degradation behavior of Mg66Zn29Ca5 bulk metallic glass was not affected by surface roughness. The surface of the Mg66Zn29Ca5 bulk metallic glass samples polished via #800 grade sandpaper was found to offer a well-attached surface and to provide a good cell viability environment for Human MG63 osteoblast-like cell line. In parallel, more calcium and mineral deposition was investigated on extracellular matrix with higher surface roughness that verify the relationship between surface roughness and cell performance.

scholarly journals Revealing Nanoindentation Size-Dependent Creep Behavior in a La-Based Metallic Glassy Film

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1712
Author(s):  
Yi Ma ◽  
Yuxuan Song ◽  
Taihua Zhang
Keyword(s):  
Metallic Glass ◽  
Size Effect ◽  
Creep Strain ◽  
Creep Behavior ◽  
Creep Deformation ◽  
Creep Resistance ◽  
Depth Effect ◽  
Size Dependent ◽  
The Relationship ◽  
Strain Dependent

We systematically studied nanoindentation size effect on creep deformation in a La-based metallic glassy film, including holding depth effect and indenter size effect. Creep displacement was mainly dependent on both holding strain and deformation volume beneath indenter. Under elastic holding, creep strain was merely holding strain–dependent. While for plastic holding, creep strain was greatly enhanced by adopting smaller indenter and/or decreasing holding depth at the same holding strain. A strong nanoindentation size effect on creep resistance was validated. Strain rate sensitivities (SRS) were calculated, which were obviously higher at elastic regions than at plastic holdings. The relationship between SRS value and creep mechanism in metallic glass was discussed.

Microstructure and Mechanical Properties Development in Cross Roll Rolled Ni-30Cr Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 2462-2467
Author(s):  
Kuk Hyun Song ◽  
Han Sol Kim ◽  
Won Yong Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Effective Strain ◽  
Initial Material ◽  
Grain Boundary Character ◽  
Microstructure And Mechanical Properties ◽  
Cold Rolled ◽  
Conventional Rolling ◽  
The Relationship ◽  
Electron Back Scattered Diffraction

In order to evaluate the microstructure and mechanical properties of cross roll rolled Ni-30Cr alloy, comparing with conventionally rolled material, this work was carried out. The materials were cold rolled to 90% in thickness reduction by conventional rolling and cross roll rolling methods and subsequently annealed at 700°C for 30 min. After this work, in order to evaluate the grain boundary character distributions of the materials, electron back-scattered diffraction technique was introduced. The application of cross roll rolling was more effective to develop the microstructure and mechanical properties than those of conventional rolling. As a result, the grain size was significantly refined to 1.3 μm in conventional rolling and 0.6 μm in cross roll rolling, compared to initial material (30 μm), respectively. Also, these grain refinements directly affected an increase in mechanical properties. In the present study, we systematically discussed the relationship between grain size and mechanical properties in terms of an increase in effective strain.

A Comparative Study of Molecular Motion Cooperativity in Polymeric and Metallic Glass-Forming Liquids

2016 ◽  
Vol 879 ◽  
pp. 151-156 ◽  
Author(s):  
Masaru Aniya ◽  
Masahiro Ikeda ◽  
Sahara
Keyword(s):  
Metallic Glass ◽  
Bond Strength ◽  
Comparative Study ◽  
Coordination Number ◽  
Molecular Motion ◽  
Fragility Index ◽  
Glass Forming ◽  
Cooperative Relaxation ◽  
The Difference ◽  
The Relationship

In order to investigate the relationship between the bonding nature and the cooperative relaxation, a comparative study of the relaxation behavior in polymeric and metallic glass forming systems has been performed based on the Bond Strength–Coordination Number Fluctuation (BSCNF) model developed by the authors. In the present work, we studied the correlations between the fragility m, the Vogel temperature T0, the degree of molecular cooperativity NB, and the Kohlrausch exponent βKWW. The results show that T0 and NB increase, whereas βKWW decreases systematically with the increase of m. Reflecting the difference of the interatomic interactions of the materials considered, the analysis by the present study reveals that the value of NB in ion-conducing polymers is about 5 times larger than that in metallic systems, and for each system, the material dependence of βKWW is clearly seen in the fragility index m and the cooperativity NB.

The relationship between t-ZrO2 stability and the crystallization of a Zr-based bulk metallic glass during oxidation

2012 ◽  
Vol 31 ◽  
pp. 21-25 ◽  
Author(s):  
Dongya Huang ◽  
Lu Huang ◽  
Bin Wang ◽  
Vincent Ji ◽  
Tao Zhang
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
The Relationship

Similarity Relationships in Creep Contacts and Applications in Nanoindentation Tests

2009 ◽  
Vol 1224 ◽  
Author(s):  
Jinhaeng Lee ◽  
Cong Zhou ◽  
Caijun Su ◽  
Yanfei Gao ◽  
George Pharr
Keyword(s):  
Strain Rate ◽  
Effective Strain ◽  
Rate Sensitivity ◽  
Amorphous Selenium ◽  
Coarse Grained ◽  
Indentation Hardness ◽  
Effective Strain Rate ◽  
Rate Dependent ◽  
Constitutive Parameters ◽  
The Relationship

AbstractThe study of indentation responses of rate-dependent (viscoplastic or creeping) solids has generally focused on the relationship between indentation hardness and an effective strain rate, which can be defined from a similarity transformation of the governing equations. The strain rate sensitivity exponent can be determined from the slope of a log-log plot of the hardness versus effective strain rate, while determining other constitutive parameters requires a knowledge of the relationship between contact size, shape, and indentation depth. In this work, finite element simulations have shown that the effects of non-axisymmetric contact and crystallography are generally negligible. Theoretical predictions agree well with real nanoindentation measurements on amorphous selenium when tested above glass transition temperature, but deviate quite significantly for experiments on high-purity indium, coarse-grained aluminum, and nanocrystalline nickel. Such a discrepancy is likely to result from the transient creep behavior.

Visualization of Stress Distribution Using Smart Mechanoluminescence Sensor

2009 ◽  
Vol 614 ◽  
pp. 169-174 ◽  
Author(s):  
Wen Xue Wang ◽  
T. Matsubara ◽  
Y. Takao ◽  
Y. Imai ◽  
Chao Nan Xu
Keyword(s):  
Stress Distribution ◽  
Light Intensity ◽  
Solid Mechanics ◽  
Effective Strain ◽  
Ccd Camera ◽  
Equivalent Strain ◽  
Element Analysis ◽  
Film Sensor ◽  
The Relationship ◽  
Visual Light

This paper describes a study on the application of smart mechanoluminescence (ML) sensor to structures for the visualization of stress distribution. Smart thin film sensor of ML material SrAl2O4:Eu/polyme is coated on the surface of structure. The sensor will emit visual light when the structure is subjected to deformation. The light intensity is proportional to the strain energy density and the equivalent strain of the stressed material based on the energy viewpoint and experimental facts. The distribution of visual light intensity is recorded using CCD camera or ordinary camera. Then the stress distribution can be evaluated from the distribution of visual light intensity based on solid mechanics and the relationship between light intensity and equivalent strain. Compression test of a disk with coated SrAl2O4:Eu/epoxy film sensor is conducted to compare the visual light distribution with the stress distribution obtained from finite element analysis. Furthermore, tensile test of a rectangular specimen with a coated SrAl2O4:Eu/polymer film sensor is performed to demonstrate the relationship between visual light intensity and strain. Experimental and numerical results show that the smart sensor of ML material SrAl2O4:Eu/polymer is an effective strain sensor to directly visualize the stress distribution in real time.

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