scholarly journals Anneal hardening effect in sintered copper alloys

2002 ◽  
Vol 34 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Svetlana Nestorovic ◽  
Boran Milicevic ◽  
Desimir Markovic
Keyword(s):  
Electrical Conductivity ◽  
Cold Rolling ◽  
Copper Alloys ◽  
Recrystallization Temperature ◽  
Temperature Range ◽  
Hardening Effect ◽  
Sintered Copper ◽  
Anneal Hardening ◽  
Cold Rolled

Samples of copper and copper alloys CuNi and CuNiAl were prepared by a powder metallurgical method and were then subjected to cold rolling with different degrees of deformation. Copper and copper alloys in the cold-rolled state were isochronally annealed up to the recrystallization temperature during which hardness and electrical conductivity were measured. This investigation shows that the anneal hardening effect occurs in a temperature range of 450 - 650 K, followed with an increase in hardness of alloys.

scholarly journals Influence of deformation degree at cold-rolling on the anneal hardening effect in sintered copper-based alloys

2004 ◽  
Vol 40 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Svetlana Nestorovic
Keyword(s):  
Cold Rolling ◽  
Annealing Temperature ◽  
Pure Copper ◽  
Deformation Degree ◽  
Temperature Range ◽  
Hardening Effect ◽  
Sintered Copper ◽  
Anneal Hardening

Samples of copper-based alloys, Cu-4at%Zn, Cu-8at%Zn and Cu-5at%Ni-2at%Sn and pure copper have been prepared by a powder metallurgical method. The samples were subjected to cold rolling to 30, 50 and 70% in reduction, followed by annealing up to the recrystallization temperatures. Anneal hardening effect has been observed with the alloys in an annealing temperature range of 180-4000C, the hardness being increased with the amount of reduction at the prior cold - rolling.

scholarly journals Influence of time of annealing on anneal hardening effect of a cast CuZn alloy

2003 ◽  
Vol 39 (3-4) ◽  
pp. 489-497 ◽  
Author(s):  
Svetlana Nestorovic ◽  
Lj. Ivanic ◽  
Desimir Markovic
Keyword(s):  
Copper Alloy ◽  
Cold Work ◽  
Pure Copper ◽  
Lattice Parameter ◽  
Recrystallization Temperature ◽  
X Ray ◽  
Hardening Effect ◽  
Anneal Hardening ◽  
Cold Rolled ◽  
Cuzn Alloy

Investigated cast copper alloy containing 8at%Zn of a solute. For comparison parallel specimens made from cast pure copper. Copper and copper alloy were subjected to cold rolling with different a final reduction of 30,50 and 70%. The cold rolled copper and copper alloy samples were isochronally and isothermally annealed up to recrystallization temperature. After that the values of hardness, strength and electrical conductivity were measured and X-ray analysis was performed. These investigations show that anneal hardening effect at alloys was attained under recrystallization temperature in the temperature range of 180-3000C, followed with an increase in hardness. The amount of strengthening increase with increasing degree of prior cold work. Also the X-ray analysis show the change of lattice parameter during annealing when anneal hardening effect was attained.

Combined Effect of Cold-Rolling and Aging on Precipitation and Recrystallization Behavior of Al-Er-Zr Alloy

2016 ◽  
Vol 877 ◽  
pp. 310-314
Author(s):  
Tong Hui Liu ◽  
Sheng Ping Wen ◽  
Xiao Lan Wu ◽  
Kun Yuan Gao ◽  
Hui Huang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Cold Rolling ◽  
Strong Interaction ◽  
Recrystallization Temperature ◽  
Precipitation Process ◽  
Recrystallization Behavior ◽  
Hardness Curve ◽  
Peak Aging ◽  
Cold Rolled ◽  
Zr Alloy

To investigate the effect of cold-rolling and aging on precipitation and recrystallization behavior of Al-0.04Er-0.08Zr (at. %) alloy, two thermo-mechanical processes containing peak aging + cold-rolling (A+CR) and cold-rolling + isochronal aging (CR+A) were studied. In A+CR process, the hardness of alloy under cold-rolled state was much higher than the maximum obtained during isochronal aging, due to the strong interaction between precipitates and dislocations or sub-grain boundaries. Furthermore, the recrystallization temperature was 475 °C as indicated by the hardness curve. The microstructure analysis revealed that the sample annealed at 525 °C for 1 h still don’t recrystallize fully. For CR+A, it turned out that the deformation play a small role in improving the maximum of hardness. But comparing with those without deformation, the existence of deformation accelerated the rate of precipitation process and obtained higher electrical conductivity.

scholarly journals Correlation between mechanical properties and structural changes of the sintered Cu-4 at% Ag alloy during thermomechanical treatment

2008 ◽  
Vol 62 (2) ◽  
pp. 78-84
Author(s):  
Ivana Rangelov ◽  
Svetlana Nestorovic ◽  
Desimir Markovic
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Thermomechanical Treatment ◽  
Structural Changes ◽  
Solute Segregation ◽  
Recrystallization Temperature ◽  
Micro Structure ◽  
Deformation Degree ◽  
Sintered Copper ◽  
Anneal Hardening

Influence of thermomechanical treatment on micro structure and strength (hardness and microhardness) of the sintered copper based Cu-4 at% Ag alloy was investigated using Vickers hardness and microhardness measurements, and optical microscopy. After sintering at 790?C, samples of Cu-4 at% Ag alloy were subjected to thermomechanical treatment by cold rolling with 20, 40 and 60% deformation degrees, and annealing below and over the recrystallization temperature. It was shown that microstructure of Cu-4 at% Ag alloy changed with thermomechanical treatment, which directly causes changes of mechanical properties. Optical microphotograph of the sintered Cu-4 at% Ag alloy shows relatively homogeneous structure with spherical pores presented. The strength (hardness and microhardness) of the sintered Cu-4 at% Ag alloy during cold rolling increases with deformation degree due to deformation strengthening. Maximum values of hardness and microhardness were for 60% deformation. The porosity still exists in spite of the fact that compacting was carried out during the cold rolling. The hardness and microhardness continue to increase after annealing at temperature bellow recrystallization temperature due to anneal hardening effect which occurs in a temperature range of 160-350?C. It was concluded that solute segregation to dislocations, analogous to the formation of Cottrel atmosphere in interstitial solid solutions, is primarily responsible for anneal hardening phenomenon. Annealing at higher temperatures (higher than 400?C) results in strength decrease due to beginning of alloy recrystallization.

scholarly journals Effect of Carbide Size, Cold Reduction and Heating Rate in Annealing on Deep-Drawability of Low-Carbon, Capped Cold-Rolled Steel Sheet

1978 ◽  
Vol 3 (1) ◽  
pp. 53-72 ◽  
Author(s):  
Kazuo Matsudo ◽  
Takayoshi Shimomura ◽  
Osamu Nozoe
Keyword(s):  
Cold Rolling ◽  
Heating Rate ◽  
Cold Reduction ◽  
Recrystallization Temperature ◽  
Rolled Steel ◽  
Low Carbon ◽  
Initial State ◽  
Cold Rolled Steel ◽  
Carbide Size ◽  
Cold Rolled

The effects of carbide size prior to cold rolling, cold reduction and heating rate in annealing on r¯-value, and texture of cold-rolled steel sheets were investigated. The main results obtained were as follows: (1) When the carbide size prior to cold rolling is large, r¯-value can be improved with a faster heating rate in annealing. (2) Moreover, the cold reduction of peak r¯-value shifts to the higher cold reduction side, and r¯-value tends to increase with cold reduction up to 90%. These phenomena are thought to be based on the delay in dissolution of carbide at the initial state of recrystallization, the change in recrystallization temperature and the preferred nucleation.

Facilitated Recrystalization of the Hard-to-Recrystalize Structure in 16% Cr Steel Sheets by one-Pass ECAP Prior to Cold Rolling

2011 ◽  
Vol 702-703 ◽  
pp. 607-610
Author(s):  
Hiroyuki Miyamoto ◽  
Tong Xiao ◽  
Toshiyuki Uenoya
Keyword(s):  
Cold Rolling ◽  
Strain Path ◽  
Equivalent Strain ◽  
Recrystallization Temperature ◽  
Deformation Bands ◽  
Final Annealing ◽  
Steel Sheets ◽  
Novel Approach ◽  
Cold Rolled ◽  
Strain Path Change

The extended band structures of cold-rolled high Cr steel sheets are recrystallization resistant, and tend to become the so-called grain colony as a recovered state. It is shown that a novel approach involving strain-path change by introducing one-pass ECAP prior to cold rolling facilitated recrystallization. Indeed, recrystallization temperature was reduced by 100 °C, compared with cold rolling alone imposing the same equivalent strain. Dense deformation bands introduced during ECAP perturbed the banded structures and enhanced the recrystallization at final annealing.

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