Room-Temperature Deformation Behavior in the Localized Regions W-80vol%Cu Composite

2006 ◽  
Vol 15-17 ◽  
pp. 255-260
Author(s):  
H. Hanado ◽  
Yutaka Hiraoka
Keyword(s):  
Plastic Strain ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Testing Machine ◽  
Temperature Deformation ◽  
High Magnification ◽  
Bend Testing ◽  
Before And After ◽  
Point Bend ◽  
Heterogeneous Deformation

Room-temperature deformation behavior in the localized regions of W-80vol%Cu composite was investigated in this study. Plastic strain of about 10 % was added to the specimen at room temperature using a three-point bend testing machine. Then deformation behavior in a localized region was investigated using a high-magnification SEM photograph before and after deformation. Results are summarized as follow. (1) In a localized region near a large pore, heterogeneous deformation had occurred as expected. (2) In a region apart from a pore, mostly homogeneous deformation occurred but occasionally heterogeneous deformation occurred.

scholarly journals The Prospects for Mechanical Ratcheting of Bulk Metallic Glasses

2003 ◽  
Vol 806 ◽  
Author(s):  
Wendelin J. Wright ◽  
R. H. Dauskardt ◽  
W. D. Nix
Keyword(s):  
Plastic Strain ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Tensile Axis ◽  
Uniaxial Stress ◽  
Temperature Deformation ◽  
Steel Alloys ◽  
Cyclic Torsion ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

ABSTRACTThe major mechanical shortcoming of metallic glasses is their limited ductility at room temperature. Monolithic metallic glasses sustain only a few percent plastic strain when subjected to uniaxial compression and essentially no plastic strain under tension. Here we describe a room temperature deformation process that may have the potential to overcome the limited ductility of monolithic metallic glasses and achieve large plastic strains. By subjecting a metallic glass sample to cyclic torsion, the glass is brought to the yield surface; the superposition of a small uniaxial stress (much smaller than the yield stress) should then produce increments in plastic strain along the tensile axis. This accumulation of strain during cyclic loading, commonly known as ratcheting, has been extensively investigated in stainless and carbon steel alloys, but has not been previously studied in metallic glasses. We have successfully demonstrated the application of this ratcheting technique of cyclic torsion with superimposed tension for polycrystalline Ti–6Al–4V. Our stability analyses indicate that the plastic deformation of materials exhibiting elastic–perfectly plastic constitutive behavior such as metallic glasses should be stable under cyclic torsion, however, results obtained thus far are inconclusive.

Extensive deformation behavior of an all-oxide Al2O3-TiO2 nanostructured multilayer ceramic at room temperature

2009 ◽  
Vol 24 (11) ◽  
pp. 3387-3396 ◽  
Author(s):  
Arcan F. Dericioglu ◽  
Y.F. Liu ◽  
Yutaka Kagawa
Keyword(s):  
Cross Sections ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Temperature Deformation ◽  
Relative Movement ◽  
Element Simulation ◽  
Columnar Grains ◽  
Multilayer Ceramic ◽  
Extensive Deformation ◽  
Indentation Response

An all-oxide Al2O3-TiO2 ceramic multilayer composed of 10–100 nm thick alternating layers was fabricated using the reactive magnetron sputtering process. Microindentation tests were carried out on the multilayer ceramic followed by microstructural observations of the cross-sections of the indented sites to characterize the indentation response of the system. During the observations, it was noted that an extensive room temperature “deformation” occurred in the multilayer ceramic material. The material shows a thickness reduction of as much as ∼40% under a conical indenter at 300 mN of load without microcracking and dislocation-assisted deformation. The room temperature deformation mechanism is governed by the relative movement and rearrangement of the anisotropic nanoscale columnar grains along the intergranular boundaries containing elongated voids. The relative sliding along the intergranular boundaries, and the subsequent granular rotation under indentation were well captured by finite element simulation.

Mechanical Properties of Winding Conductors Affected by Cyclic Thermal Overloads

2006 ◽  
Vol 113 ◽  
pp. 541-544 ◽  
Author(s):  
N. Višniakov ◽  
J. Novickij ◽  
D. Ščekaturovienė ◽  
M. Šukšta
Keyword(s):  
Mechanical Properties ◽  
Metal Matrix ◽  
Room Temperature ◽  
Pure Copper ◽  
Testing Machine ◽  
Liquid Nitrogen Temperature ◽  
Ultimate Tensile Stress ◽  
Climatic Chamber ◽  
Fast Heating ◽  
Before And After

The influence of thermal cyclic overloads on mechanical properties of winding conductors was investigated. Copper-niobium microcomposite, soft and hard pure copper wires were conditioned at temperatures range from 77 K to 500 K. The treatment was done during 100 cycles of fast conductor cooling to liquid nitrogen temperature and further fast heating in a climatic chamber. The ultimate tensile stress limit and the elongation at failure of metal-matrix copper-niobium microcomposite, soft and hard copper wires were measured before and after thermal treatment with a testing machine at room temperature.

scholarly journals Room Temperature Deformation Behavior of Zn-22 mass%Al Alloy with Nanocrystalline Structure

2002 ◽  
Vol 43 (10) ◽  
pp. 2449-2454 ◽  
Author(s):  
Tsutomu Tanaka ◽  
Koichi Makii ◽  
Atsumichi Kushibe ◽  
Kenji Higashi
Keyword(s):  
Deformation Behavior ◽  
Room Temperature ◽  
Nanocrystalline Structure ◽  
Temperature Deformation ◽  
Al Alloy
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