scholarly journals Effect of Cd and SPD on structure, physical, mechanical, and operational properties of alloy of Cu-Cr-Zr

2020 ◽  
Vol 59 (1) ◽  
pp. 506-513
Author(s):  
Denis A. Aksenov ◽  
Georgiy I. Raab ◽  
Rashid N. Asfandiyarov ◽  
Vladimir I. Semenov ◽  
Lev Sh. Shuster
Keyword(s):  
Wear Resistance ◽  
Structure Refinement ◽  
Alloy System ◽  
Environmental Safety ◽  
Structural Refinement ◽  
Industrial Systems ◽  
Ultrafine Grained ◽  
Positive Effect ◽  
Complete Processing ◽  
Zr Alloy

AbstractAn increase in the service life of electrical products from copper and its alloys is directly related to an increase in the wear resistance of materials. Structural refinement and alloying with cadmium are known to have a positive effect on the strength characteristics and wear resistance of copper, which makes it possible, with a Cd content of 1% by weight, to increase the wear resistance of copper several times, but cadmium is considered an environmentally unsafe element. In this regard, the paper presents the results of studies of a widely used Cu-Cr-Zr alloy system in the ultrafine-grained (UFG) state, micro-alloyed with cadmium (0.2%, weight), in order to improve physical, mechanical, and operational properties, as well as environmental safety. Severe plastic deformation, providing structure refinement to ~150 nm, and microalloying with cadmium of a Cu-Cr-Zr system alloy, after a complete processing cycle, provides a tensile strength of 570±10 MPa and 67% electrical conductivity. At the same time, the abrasion resistance increases by 12 and 35% relative to the industrial systems Cu-Cd and Cu-Cr-Zr, respectively. The obtained characteristics are very promising for improving the operational properties of continuous welding tips, collector plates, and contact wires operating under conditions of intense wear.

Wear resistance of an ultrafine-grained Cu-Zr alloy processed by equal-channel angular pressing

Wear ◽  
2015 ◽  
Vol 326-327 ◽  
pp. 10-19 ◽  
Author(s):  
Jianwei Li ◽  
Jittraporn Wongsa-Ngam ◽  
Jie Xu ◽  
Debin Shan ◽  
Bin Guo ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Equal Channel Angular Pressing ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Zr Alloy

New solutions to the problems of chain orientation and chain continuity in structure analysis of fibrous polymers. A reconsideration of the structure of polyisobutene

2007 ◽  
Vol 40 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Attilio Immirzi ◽  
Davide Alfano ◽  
Consiglia Tedesco
Keyword(s):  
New York ◽  
Degrees Of Freedom ◽  
Structure Refinement ◽  
General Interest ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Chain Orientation ◽  
Crystalline Polymers ◽  
Internal Coordinates ◽  
Fibrous Polymers

Two points of general interest in structural refinement of polymers based on internal coordinates are discussed: the chain orientation and the chain continuity. Using a proprietary computer program, based on revised approaches to these questions, the structure of polyisobutene has been reconsidered, using new X-ray diffraction measurements (Fuji image plate) and performing a structure refinement based on internal coordinates. Three refinement schemes, with a decreasing number of degrees of freedom, have been considered, with the conclusion that the distortion from the 83regular helix, claimed by Tadokoro [(1979).Structure of Crystalline Polymers, p. 136. New York: Wiley-Interscience], is confirmed, though lower than supposed. The new procedures implemented for chain orientation and chain continuity work excellently.

Ultrafine-grained Mg-Zn-Y-Zr alloy with remarkable improvement in superplasticity

2021 ◽  
pp. 130524
Author(s):  
Huizi Chen ◽  
Jian Wang ◽  
Xiangchen Meng ◽  
Yuming Xie ◽  
Yulong Li ◽  
...  
Keyword(s):  
Remarkable Improvement ◽  
Ultrafine Grained ◽  
Zr Alloy

Microstructure and Aging Behavior of Al-0.2wt%Zr Alloy Heavily Deformed by ARB Process

2008 ◽  
Vol 584-586 ◽  
pp. 728-733 ◽  
Author(s):  
Takatoshi Sato ◽  
Daisuke Terada ◽  
Nobuhiro Tsuji
Keyword(s):  
Grain Size ◽  
Microstructural Evolution ◽  
Coarse Grain ◽  
Aging Behavior ◽  
Roll Bonding ◽  
Solution Treated ◽  
Ultrafine Grained ◽  
Mean Grain Size ◽  
Treated State ◽  
Zr Alloy

An Al-0.2wt%Zr alloy was severely deformed up to a strain of 8.0 by accumulative roll bonding (ARB) process, started from the solution-treated state. The microstructural evolution during ARB and its aging behavior were investigated. With increasing the number of ARB cycles, Vickers hardness of the specimens increased and reached to a constant value. The microstructural evolution during the ARB could be understood in terms of grain subdivision. The ultrafine grained (UFG) materials whose mean grain size was 0.4 -m were obtained by 10-cycle ARB process. In aging of the ARB processed specimens at high temperatures above 673K, the UFG microstructures quickly coarsened. On the other hand, it was suggested that the precipitation behaviors of the ARB specimen at 623K were quite unique and completely different from those of the conventionally solution-treated material with coarse grain size.

Microstructure and Abrasion Resistance of WC-Co Coatings Produced by High Velocity Oxy-Fuel Spraying

1997 ◽  
Author(s):  
M.S.A. Khan ◽  
T.W. Clyne ◽  
A.J. Sturgeon
Keyword(s):  
Wear Resistance ◽  
High Velocity ◽  
Abrasion Resistance ◽  
Close Correlation ◽  
Low Oxygen ◽  
Hvof Spraying ◽  
Degree Of Reaction ◽  
Small Rise ◽  
Negative Effect ◽  
Positive Effect

Abstract Coatings have been produced by HVOF spraying of four different WC-Co powders, using two fuel gases and two oxygen contents in the flame, and characterised in terms of microstructure and resistance to abrasive wear. It is concluded that there is a close correlation between high levels of chemical reaction, occurring during spraying (and possibly during powder production), and poor wear resistance. Good wear resistance is favoured by using low porosity powders, which interact with the atmosphere less readily during spraying, and also by using a flame with a relatively low oxygen content. This probably minimises the degree of reaction by ensuring that conditions are reducing. Use of propylene rather than hydrogen gives coatings with slightly better wear resistance, despite the fact that the flame temperatures are higher. It is concluded that, for this relatively small rise in temperature, the positive effect on inter-splat cohesion seems to outweigh the negative effect of increased decarburisation.

Annealing Effects in Conventionally Cast and Homogenized Al-Zn-Mg(-Sc-Zr) Alloy

2017 ◽  
Vol 380 ◽  
pp. 167-172
Author(s):  
Martin Vlach ◽  
Veronika Kodetova ◽  
Bohumil Smola ◽  
Hana Kudrnova ◽  
Tomáš Kekule
Keyword(s):  
Electron Microscopy ◽  
Supersaturated Solid Solution ◽  
Microstructure Development ◽  
Scanning Calorimetry ◽  
Zr Addition ◽  
Annealing Effects ◽  
Positive Effect ◽  
Scanning Electron ◽  
Zr Alloy ◽  
Conventionally Cast

Al-based alloys are very preferred for automotive manufacture to produce lightweight vehicles. The positive effect of Sc,Zr-addition on the mechanical properties in Al-based alloys is generally known. Microstructure, mechanical, electrical and thermal properties of the conventionally cast and homogenized Al–Zn–Mg alloy with and without Sc,Zr-addition during isochronal annealing were studied. The electrical resistometry and microhardness together with differential scanning calorimetry measurements were compared to microstructure development that was observed by optical microscopy and transmission and scanning electron microscopy. It was observed that the Sc,Zr-content in the alloy after casting is not homogeneously distributed but concentrated in randomly localized matrix regions and together with Zn and Mg in the particles at grain boundaries. However, the hardening effect after annealing above 280 °C lightly reflects the Sc,Zr-addition. The distinct changes in resistivity and microhardness as well as in heat flow of the alloys studied are mainly caused by formation/dissolution of the Guinier-Preston zones and subsequent precipitation of the metastable particles from the Al–Zn–Mg system. The eutectic Zn,Mg-containing phase partly disappeared during the annealing above ~ 390 °C. Melting of the Zn,Mg-containing phase was observed at ~ 475 °C. The decomposition sequence of the supersaturated solid solution of the studied alloys is compatible with the decomposition sequence of the Al–Zn–Mg system minimally up to ~ 380 °C.

scholarly journals Effect of Heat Treatment on the Microstructure and Properties of Ultrafine WC–Co Cemented Carbide

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1302
Author(s):  
Zhongnan Xiang ◽  
Zhanjiang Li ◽  
Fa Chang ◽  
Pinqiang Dai
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Service Life ◽  
Treatment Process ◽  
Cutting Conditions ◽  
Cemented Carbide ◽  
Cemented Carbides ◽  
Heat Treatment Process ◽  
Microstructure And Properties ◽  
Ultrafine Grained

In this paper, the effect of heat treatment on the microstructure and properties of a 0.8 μm WC–10%Co ultrafine cemented carbide was studied. The results show that the microstructural differences in ultrafine WC–Co cemented carbides without and with heat treatment are mainly reflected in the Co phase. For conventional cemented carbides, the hardness and wear resistance can be increased only at the expense of the toughness and strength. An ultrafine-grained WC–Co cemented carbide with good hardness and toughness can be obtained by strengthening the Co phase through an appropriate heat treatment process, and the service life of the ultrafine-grained WC–Co cemented carbide can be improved under actual cutting conditions.

Significantly Enhanced Wear Resistance of an Ultrafine-Grained CrFeNi Medium-Entropy Alloy at Elevated Temperatures

2020 ◽  
Vol 51 (6) ◽  
pp. 2834-2850
Author(s):  
Dingshan Liang ◽  
Cancan Zhao ◽  
Weiwei Zhu ◽  
Pengbo Wei ◽  
Feilong Jiang ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Elevated Temperatures ◽  
Ultrafine Grained
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