scholarly journals Effect of aging on properties and nanoscale precipitates of Cu-Ag-Cr alloy

2020 ◽  
Vol 9 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Lingbao Kong ◽  
Yanjun Zhou ◽  
Kexing Song ◽  
David Hui ◽  
Hao Hu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Aging Time ◽  
Aging Process ◽  
Copper Matrix ◽  
Micro Hardness ◽  
Hardness Increase ◽  
Change Trend ◽  
Effects Of Aging ◽  
High Level ◽  
Elemental Form

AbstractIn this paper, the Cu-0.52Ag-0.22Cr alloy was prepared by hot horizontal continuous casting. The effects of aging process on micro-hardness, electrical conductivity, and nanoscale precipitates of Cu-0.52Ag-0.22Cr alloy were studied. The electrical conductivity and micro-hardness increase significantly in the early aging time. With the extension of aging time, the electrical conductivity is basically unchanged and remains at a high level. While, the micro-hardness increases slowly, the change trend is different at 623 K, 723 K, and 773 K. The optimisation of process parameters occurs in 723 K for 2 h. At this time, the electric conductivity is 95.8% IACS and the hardness is 104.1 HV0.1. The XRD result shows that the Ag and Cr are precipitated in elemental form copper matrix. Further TEM shows that, Cr exists at the sub-boundary in the form of larger nanoscale precipitates (100-200 nm). While a large number of Ag nanoscale precipitates (8-10 nm) is dispersed on the copper matrix. The synergistic effect of Ag and Cr nanoscale precipitates significantly improved the properties of the alloy.

Effects of Aging on the Solubility of Palladium

1995 ◽  
Vol 412 ◽  
Author(s):  
C. Oda ◽  
H. Yoshikawa ◽  
M. Yui
Keyword(s):  
Aqueous Solution ◽  
Aging Time ◽  
Room Temperature ◽  
High Level Waste ◽  
Anaerobic Conditions ◽  
Dilute Aqueous Solution ◽  
Waste Repository ◽  
Ph Range ◽  
Effects Of Aging ◽  
High Level

AbstractPalladium solubility was measured in a dilute aqueous solution at room temperature in the pH range from 3 to 13 under anaerobic conditions. Crystalline Pd metal was clearly visible and the concentration of palladium in solution decreased gradually with aging time. The palladium concentrations in solution were less than 9.4×10-10M in the pH range from 4 to 10 and increased to 10-7M in the pH range greater than 10. This study suggests that palladium concentrations in certain high-level waste repository environments may be limited by Pd metal and may be less than 10-9M.

The Microstructure Stability of Super304H Steel Aging at 750°C

2017 ◽  
Vol 898 ◽  
pp. 730-734
Author(s):  
Bao Lan Gu ◽  
Jian Xin Dong ◽  
Tong Xu
Keyword(s):  
Aging Time ◽  
Aging Process ◽  
Austenitic Matrix ◽  
Rich Phase ◽  
Microstructure Stability ◽  
Initial Stage ◽  
Hardness Increase ◽  
Precipitated Phases ◽  
Aging Stage ◽  
Super304h Steel

The microstructure stability and the effect of microstructure evolution on the properties of Super304H steel aged at 750°C for different time were investigated. The results showed that the microstructure of the Super304H steel after aging at 750°C consists of primary matrix and large amount of precipitated phases. The main precipitates were Cu-rich phase, MX phase and M23C6 carbides in austenitic matrix during aging. The M23C6 carbides precipitate preferentially at grain boundaries, and then coarsening remarkably with increasing aging time. The MX phase was stable during the whole aging process. The Cu-rich particle is smaller than 10 nm at the initial aging stage, and then coarsen with increasing aging time. The strength and hardness increase obviously at the initial stage due to the interaction of Cu-rich phase, MX phase and M23C6 carbides precipitation strength, in which Cu-rich phase strengthen action is the dominant. Coarsening M23C6 carbides weaken the strength during aging.

Optimization of Heat Treatment Parameters with the Taguchi Method for the A7050 Aluminum Alloy

2010 ◽  
Vol 139-141 ◽  
pp. 157-162 ◽  
Author(s):  
Chin Chun Chang ◽  
Ji Gang Yang ◽  
Ling Qi ◽  
Chang Pin Chou
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Aluminum Alloy ◽  
Taguchi Method ◽  
Aging Time ◽  
Aging Temperature ◽  
Ageing Time ◽  
Ageing Temperature ◽  
Micro Hardness ◽  
Optimization Criteria

This paper describes a heat treatment process using dual aging for the A7050 aluminum alloy with the Taguchi method to optimize process parameters. The current study considers micro hardness and electrical conductivity as optimization criteria. Pre-aging temperature, pre-aging time, re-aging temperature, and re-aging time are important factors influencing these optimization criteria. Experiment results show that re-aging temperature is the most significant parameter for electrical conductivity, and both aging times are important influence factors for micro hardness performance. The optimal hardness for A7050 heat treatment conditions are pre-ageing temperature 120 °C, pre-ageing time 12hrs., re-aging temperature140 °C, and re-aging time 8 hrs., respectively. The best electrical conductivity parameters are pre-ageing temperature 120 °C, pre-ageing time 4 hrs., re-aging temperature180 °C, and re-aging time 24 hrs., respectively. The current study obtained contributing individual parameters for hardness, and electrical conductivity in dual aging of heat treatment.

Effect of Two-Step Deforming and Aging Process on the Properties and Microstructure of Cu-Cr-Zr-Mg-Si Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 70-74
Author(s):  
Jian Yi Cheng ◽  
Fang Xin Yu ◽  
Xue Wen Ao
Keyword(s):  
Electrical Conductivity ◽  
Aging Process ◽  
Cold Deformation ◽  
Copper Matrix ◽  
Single Step ◽  
Overall Performance

Effect of two-step deforming and aging process on the properties and structure of Cu-Cr-Zr-Mg-Si alloy was investigated. The results show under the condition of same cold deformation, two-step deforming and aging processes can improve overall performance of the alloy. The hardness obtained by two-step deforming and aging process is higher 6%-9% than that by single-step deforming and aging. The hardness and conductivity are up to 160HV and 88.1% IACS respectively after 80 % rolling and reaging at 480°C for 30min. The particles precipitate along the dislocation and pin on the dislocation during the reaging. These finer particles distribute more uniformly in the copper matrix and result in the higher strength and electrical conductivity.

Effects of Aging Process Exercise Program on Walking ability and Frailty of Elderly Women in Rural

2018 ◽  
Vol 27 (2) ◽  
pp. 1115-1126 ◽  
Author(s):  
Seul-Hee Lee ◽  
Ga-Ram Hong ◽  
Bong-Jo Kim ◽  
Eun-Hee Kim
Keyword(s):  
Aging Process ◽  
Elderly Women ◽  
Exercise Program ◽  
Walking Ability ◽  
Effects Of Aging

scholarly journals Investigation of the microstructure evolution in TP347HFG austenitic steel at 700°C and its characterization method

2021 ◽  
Vol 40 (1) ◽  
pp. 12-22
Author(s):  
Yuetao Zhang ◽  
Tingbi Yuan ◽  
Yawei Shao ◽  
Xiao Wang
Keyword(s):  
Austenitic Steel ◽  
Aging Time ◽  
Microstructure Evolution ◽  
Precipitate Phase ◽  
Dispersion Strengthening ◽  
Micro Hardness ◽  
Dispersed Particles ◽  
Nonlinear Ultrasonic ◽  
The Matrix ◽  
Solution Strengthening

Abstract This article reports the microstructure evolution in TP347HFG austenitic steel during the aging process. The experiments were carried out at 700°C with different aging time from 500 to 3,650 h. The metallographic results show that the coherent twin and incoherent twin are existed in the original TP347HFG grains, while they gradually vanished with the increase of the aging time. After aging for 500 h, a lot of fine, dispersed particles precipitated from the matrix, but they disappeared after aging for 1,500 h. When the aging time extend to 3,650 h, the precipitates appeared apparently coarse in TP347HFG steel, which include the M23C6 and σ phase; besides, the micro-hardness of TP347HFG also changes during the aging, which was closely related to the effect of dispersion strengthening and solution strengthening. The results of the nonlinear ultrasonic measurement reveal that the β′ of TP347HFG steel was also changed with the aging time. It first increased at 0–500 h, then reduced later, and increased finally at 1,500–3,650 h. The variation of β′ in TP347HFG was influenced by a combined effect of the twin microstructure and the precipitate phase, which indicate that the nonlinear ultrasonic technique can be utilized to characterize the microstructure evolution in TP347HFG.

Fabrication of Cu-Al2O3 Composites by Simplified Internal Oxidation Process

2010 ◽  
Vol 148-149 ◽  
pp. 416-419
Author(s):  
Bao Hong Tian ◽  
Cheng Dong Xia ◽  
Shu Guo Jia
Keyword(s):  
Electrical Conductivity ◽  
Tensile Strength ◽  
Internal Oxidation ◽  
Oxidation Process ◽  
Hot Extrusion ◽  
Softening Temperature ◽  
Copper Matrix ◽  
Dispersion Strengthening ◽  
Powder Metallurgical Process ◽  
Thermal Stability Of

Cu-Al2O3 composites were prepared by a new simplified internal oxidation process integrating with powder metallurgical process, and then the hot extrusion and the cold rolling processes were carried out. The microstructure, electrical conductivity, hardness, tensile strength and thermal stability of the composites were investigated. The results show that Cu-Al2O3 composites were fabricated successfully by the simplified process in which internal oxidation completed during the sintering. There are a mass of fine Al2O3 particles in size varying from 5 nm to 20nm dispersed in copper matrix after sintering 950 for 4h. After sintered at 950 for 4h and extruded at 950 followed with the cold deforming of 80%, the electrical conductivity, hardness, tensile strength and softening temperature of composite reach 81％IACS, 137HV, 561MPa and 850 respectively. It is considered that the dispersion strengthening and strain hardening have greatly contribution to the Cu-Al2O3 composites fabricated with the simplified process.

Enhanced strength and electrical conductivity of Cu–Zr–B alloy by double deformation–aging process

2014 ◽  
Vol 615 ◽  
pp. 249-254 ◽  
Author(s):  
Youxiong Ye ◽  
Xuyue Yang ◽  
Jun Wang ◽  
Xiangkai Zhang ◽  
Zhiling Zhang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Aging Process ◽  
Deformation Aging

scholarly journals Effect of Thermal Aging on the Mechanical Properties of High Tenacity Polyester Yarn

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1666
Author(s):  
Tsegaye Sh. Lemmi ◽  
Marcin Barburski ◽  
Adam Kabziński ◽  
Krzysztof Frukacz
Keyword(s):  
Mechanical Properties ◽  
Structural Change ◽  
Aging Time ◽  
Thermal Aging ◽  
Temperature Influence ◽  
Polyester Yarn ◽  
Textile Materials ◽  
Conveyor Belts ◽  
Effects Of Aging ◽  
Vulcanization Process

Textile materials produced from a high tenacity industrial polyester fiber are most widely used in the mechanical rubber goods industry to reinforce conveyor belts, tire cords, and hoses. Reinforcement of textile rubber undergoes a vulcanization process to adhere the textile materials with the rubber and to enhance the physio-mechanical properties of the product. The vulcanization process has an influence on the textile material being used as a reinforcement. In this work, the effects of aging temperature and time on the high tenacity polyester yarn’s mechanical and surface structural properties were investigated. An experiment was carried out on a pre-activated high tenacity polyester yarn of different linear densities, by aging the yarn specimens under various aging temperatures of 140, 160, 200, and 220 °C for six, twelve, and thirty-five minutes of aging time. The tensile properties and surface structural change in the yarns pre- and post-aging were studied. The investigation illustrates that aging time and temperature influence the surface structure of the fiber, tenacity, and elongation properties of the yarn. Compared to unaged yarn, an almost five times higher percentage of elongation was obtained for the samples aged at 220 °C for 6 min, while the lowest tenacity was obtained for the sample subjected to aging under 220 °C for 35 min.

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