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 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.

Influence of Severe Thermomechanical Treatment on Formation of Nanocrystalline Structure in Ni 718 and Ni 718Plus Alloys and their Mechanical Properties

2008 ◽  
Vol 584-586 ◽  
pp. 458-463 ◽  
Author(s):  
Shamil Kh. Mukhtarov ◽  
Vener Valitov ◽  
M.F.X. Gigliotti ◽  
P.R. Subramanian ◽  
J.S. Marte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermomechanical Treatment ◽  
Structural Changes ◽  
Nanocrystalline Structure ◽  
Grain Structure ◽  
Total Strain ◽  
Recrystallization Temperature ◽  
Uniform Structure ◽  
Processing Temperature ◽  
Alloy 718

The influence of severe thermomechanical treatment via multiple forging on the formation of a nanocrystalline (NC) structure in bulk samples of Alloy 718 and ATI 718Plus has been investigated. It was observed that a step-wise decrease of processing temperature from 950 down to 575°C allowed the refinement of the initial coarse grain structure to a NC state. Investigations of structural changes in the deformed samples have shown that extending the temperature interval of dynamic recrystallization to low homologous temperatures resulted in the formation of a fine-grained recrystallized structure. The temperature of NC structure formation in ATI Alloy 718Plus was 50-100°С higher than that required for alloy 718. This was due to the presence of the additional γ′-phase, which increased the recrystallization temperature. This decreased the total strain required to produce NC structure, as compared with Alloy 718. It was observed that increasing the total strain and decreasing temperatures step-wise during deformation via multiple forging resulted in a uniform structure across the cross-section of the samples. The room temperature mechanical properties of the investigated alloys with various grain sizes are also compared.

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.

Effect of Processing Techniques on the Mechanical Property of New Zirconium Alloy Strip

2019 ◽  
Vol 944 ◽  
pp. 99-103
Author(s):  
Peng Fei Zhang ◽  
Xu Kun Hu ◽  
Guo Cheng Sun ◽  
Bo Gao ◽  
Bin Xu
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Cold Rolling ◽  
Zirconium Alloy ◽  
Cold Deformation ◽  
Second Phase ◽  
Alloy Strip ◽  
Deformation Degree ◽  
Deformation Amount ◽  
Cold Rolling And Annealing

In this paper, a typical new zirconium alloy (Zr-Sn-Nb system) was used as the research object. The zirconium alloy strip was prepared from a series of production processes from smelting. By optimizing the process of cold processing with the change of the deformation amount and the intermediate heat treatment, the mechanical properties of the zirconium alloy were studied by different processing. The results are as follows: (1) The mechanical properties of the new zirconium alloy have reached the mechanical properties of Zirlo alloy with the optimization of the alloy composition, and (2) The zirconium alloy can refine the grain strength by the control of deformation degree and annealing temperature during cold deformation. The larger of the cold deformation, the smaller the average of the grains and the higher the yield strength of the material. The yield strength of the material was decreased by cold rolling and annealing more than once; (3) The larger the cold rolling variable of the zirconium alloy in cold deformation, it is beneficial to the second phase to be fine, dispersed and uniformly distributed, thus improving the strength of the material.

Effect of Cold Rolling and Heat Treatment on Microstructure and Mechanical Properties of Pt-0.7Ti Microalloy

2015 ◽  
Vol 817 ◽  
pp. 645-650
Author(s):  
Qiong Zhao ◽  
Xiao Ge Zhang ◽  
Ye Fan ◽  
Guo Yi Qin ◽  
Si Yong Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Cold Rolling ◽  
Annealing Treatment ◽  
Recrystallization Temperature ◽  
Micro Hardness ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Rolling Deformation

The effects of cold rolling, solid solution, aging and annealing treatment on Pt-0.7Ti microalloy were investigated in this study. The microstructures of Pt-0.7Ti microalloy and the precipitated ordered phase Pt8Ti were observed and analyzed by OM, TEM, XRD. The mechanical properties of the alloy were evaluated Vicker micro-hardness. The results showed that micro amount of Ti was an effective element for solid-solution strengthening of Pt, the micro-hardness of 97% deformation for ST and ST+AG samples increased to 214HVand 224HV, respectively, which almost are double that of pure Pt. Micro-amount of long range ordered phase Pt8Ti was precipitated during the heat treatment, but the effect of order hardening in Pt-0.7Ti microalloy was not obvious. The microhardness by large rolling deformation for quenched samples almost unchanged after an annealing below 500°C for 1h, but decreased significantly at 700°C, and the recrystallization temperature was risen by 200°C than that of pure Pt.

Recrystallization Temperature Influence upon Structural Changes of 90% Cold Rolled Ti-29Nb-9Ta-10Zr Biocompatible Alloy

2013 ◽  
Vol 592-593 ◽  
pp. 370-373
Author(s):  
Cristina Mariana Tabirca ◽  
Thierry Gloriant ◽  
Doina Margareta Gordin ◽  
Isabelle Thibon ◽  
Doina Raducanu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Structural Changes ◽  
Vacuum Arc ◽  
Recrystallization Temperature ◽  
Induction Melting ◽  
X Ray Diffraction ◽  
Superior Mechanical Properties ◽  
Cold Rolled ◽  
The 1960S ◽  
Biocompatible Alloys

In recent years a significant increase in new Ti-based biocompatible alloys (such as TiTaZr or TiTa-Nb-Zr) development was reported. Titanium and its alloys have been widely used in medicine since the 1960s because of their known biocompatibility, superior mechanical properties, low density and remarkable chemical stability. The present study investigates the microstructures and the mechanical properties of a Ti-29Nb-9Ta-10Zr (wt.%) alloys in order to investigate structural changes occurred during recrystallization treatment of 90% cold rolled Ti-29Nb-9Ta-10Zr (wt.%) alloy. The investigated alloy was fabricated by vacuum arc induction melting in levitation, using a FIVES CELES MP 25 furnace, starting from elemental components. Structural changes occurred during recrystallization treatment were investigated using X-ray diffraction, using a Philip PW 3710 diffractometer, in Bragg-Brentano θ-2θ geometry, with negligible instrumental broadening. Data concerning alloys component phases, average coherent crystallite size and internal average micro-strain was obtained.

scholarly journals Effects of recrystallization annealing on mechanical properties of cold-rolled PdNi5 wires

10.30544/136 ◽  
2016 ◽  
Vol 22 (1) ◽  
pp. 17-24
Author(s):  
Aleksandra Ivanović ◽  
Biserka Trumić ◽  
Svetlana Ivanov ◽  
Saša Marjanović ◽  
Silvana Dimitrijević ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Cold Deformation ◽  
Testing Machine ◽  
Recrystallization Temperature ◽  
Time Range ◽  
Recrystallization Annealing ◽  
Deformation Degree ◽  
Cold Rolled

The aim of this investigation was to determine the influence of the recrystallization temperature and recrystallization time on the microstructure and mechanical properties of the PdNi5 alloy subjected to cold deformation in the process of rolling at a constant deformation degree. The samples of PdNi5 alloy were recrystallization annealed within the temperature range of 200-1000ºC and annealing time range of 20-45 min after cold rolling with deformation degree of 97%. The tensile test was carried out using universal material testing machine. The hardness was also measured on the combined device for measuring Vickers and Brinell hardness. Metallographic observations were performed on an optical microscope. The analysis of the results of investigations regarding the microstructural changes and corresponding mechanical properties of cold-rolled PdNi5 strips shows that annealing temperature of 500ºC was sufficient to activate the energy for various recrystallization processes causing a change in the mechanical properties of cold-rolled PdNi5 strips. The annealing time, at constant annealing temperature, almost did not affect a recrystallization temperature and the mechanical properties of the cold-rolled PdNi5 strips.

Teknologi Inokulasi Besi Cor Kelabu FC-250 Untuk Mencegah Pengerasan Pada Dove Tale Produk Ragum Tipe 125

2019 ◽  
Vol 16 (2) ◽  
Author(s):  
Amin Suhadi ◽  
Seodihono
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Treatment Process ◽  
Gray Cast Iron ◽  
Spare Parts ◽  
Gray Cast ◽  
Micro Structure ◽  
Control Factors ◽  
Seed Inoculation ◽  
Casting Industry

Production technology of metal casting industry in Indonesia needs to be improved, especially in the manufacturing of spare parts and box engine made of gray cast iron which has various wall thick such as dove tale construction. Microstructure of gray cast iron is influenced by cooling rate during casting, chemical composition and melting treatment process (inoculation). The part which has the thinnest thickness has the fastest cooling therefore, the grain boundary is smaller compared to other section. As a result this part has highest hardness and difficult to be machined. This research is conducted to solve this problem by modifying melting and solidification treatment process. The research starting from micro structure analysis, composition and mechanical properties tests on the product, and then conducting modification treatment through Taguchi method approach. Experimental results obtained show that the best level settings to control factors which affect to the uniformity of the microstructure and mechanical properties in gray cast iron is the addition of seed inoculation super ® 75, as much as 0.25% with the method of inoculation material entering into the Transfer Ladle.Teknologi produksi pada industri pengecoran di Indonesia masih membutuhkan perbaikan terutama dalam pembuatan komponen mesin perkakas dan peralatan pabrik yang terbuat dari besi tuang kelabu yang mempunyai variasi ketebalan yang besar seperti konstruksi ekor burung (dove tale). Pada pengecoran, struktur mikro dari besi tuang kelabu sangat dipengaruhi oleh kecepatan pendinginan, komposisi kimia dan proses perlakuan pada logam cair (inokulasi). Bagian yang mempunyai ukuran paling tipis mempunyai kecepatan pendinigan paling tinggi karena itu ukuran butirnya jauh lebih kecil dari bagian lain, akibatnya bagian ini mempunyai kekerasan lebih tinggi dan sulit dilakukan pengerjaan mesin. Penelitian ini bertujuan untuk memperbaiki hal ini yang terjadi pada dove taledengan cara memodifikasi proses perlakuan pada cairan besi dan proses pendinginan. Penelitian dimulai dari analisa struktur mikro, pengujian komposisi kimia, pengujian sifat mekanis pada produk kemudian dilakukan modifikasi menggunakan pendekatan metode statistik Taguchi. Hasil penelitian menunjukkan bahwa pengaturan terbaik yang dapat diperoleh untuk mendapatkan keseragaman struktur mikro dan sifat mekanis pada pengecoran besi tuang kelabu adalah penambahan seed inoculation super ® 75, sebesar 0.25% dengan metode pemasukan inokulasi kedalam Ladle pengangkut logam cair.Keywords: carbon, micro structure, hardness, inoculation

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