Effect of Heat Treatment Conditions on Microstructures and Mechanical Properties of Cu-9Ni-6Sn-0.22Nb Alloy

2021 ◽  
Vol 904 ◽  
pp. 124-130
Author(s):  
Si Yang Xu ◽  
Ying Long Li ◽  
Mu Xin Zhang ◽  
Yi Fu Jiang ◽  
Hua Ding

Due to its high strength, excellent electrical conductivity and high resistance to stress corrosion, Cu-Ni-Sn alloy has been selected as a kind of advanced metal material which can be used as the manufacture of springs, connectors, bearings and so on. In addition, the addition of Nb can efficiently improve the comprehensive properties of the alloy. In the present work, the effect of heat treatment conditions on microstructure and mechanical properties were studied in a Cu-9Ni-6Sn-0.22Nb alloy by means of optical microscopy (OM), transmission electron microscopy (TEM), tensile test and microhardness tests. The results show that before ageing, a large number of fine γ precipitates with DO22 type structure are distributed on the matrix. With the prolongation of ageing time, the ultimate tensile strength (UTS), yield strength (YS) and Vickers hardness increased firstly, and then decline. The reason can be attributed to the occurrence of spinodal decomposition and the formation of discontinuous precipitation (DP). At first, spinodal decomposition induced the enhanced interaction between dislocations and internal stress field, resulting in an increase of mechanical properties. Then the increased DP at grain boundaries leads to the decline of strength in the material. Finally, the relationship between the microstructure and the electrical conductivity was also analyzed, and the results show that the electrical conductivity increased with ageing time/ageing temperature increasing for the present alloy. Through the analysis of Matthiessen’ s rule, the variation of electrical resistivity depends on precipitates, solute atoms, dislocations, vacancies and grain boundaries, and the precipitates play an important role among them. Besides, more precipitates improve electrical conductivity. Therefore, the increase of ageing time/ageing temperature induced the increase of DP, resulting in an increase of electrical conductivity.

2018 ◽  
Vol 80 (6) ◽  
Author(s):  
D. N. Nguyen ◽  
A. T. Hoang ◽  
X. D. Pham ◽  
M. T. Sai ◽  
M. Q. Chau ◽  
...  

This paper investigates a high electrical conductivity and high strength of alloys based on Cu-Ni-Si system It proclaimed the results of the effect of tin (Sn) component on the mechanical properties and microstructure of Cu-Ni-Sn alloy. The conditions for processing the Cu-Ni-Si alloy were presented, the analysis of microstructure and mechanical properties after heat treatment was examined by X-ray, SEM, EDS and specialized machines. The results showed that with 3% mass of Sn added into the Cu-Ni-Sn alloy along with heat treatment and deformation, the hardness value reached the range of 221-240HV, the tensile strength and elastic limit reached around 1060MPa and 903MPa respectively. However, after heat treatment and deformation for the Cu-Ni-Sn alloy based on 6% mass of Sn, the hardness value reached the range of 221-318HV, the tensile strength and elastic limit were respectively 222MPa and 263MPa higher than those of the Cu-Ni-Sn alloy with 3% mass of Sn. The result from X-ray analysis showed the deflection of peaks. Nonetheless, the new phases were not observed in SEM and EDS, contrariwise, generated modular structure was considered as the proof of the Spinodal cluster. This fact might be explained by two mechanisms: deformation mechanism and Spinodal decomposition.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 647 ◽  
Author(s):  
Bingrong Zhang ◽  
Lingkun Zhang ◽  
Zhiming Wang ◽  
Anjiang Gao

In order to obtain high-strength and high-ductility Al–Si–Cu–Mg alloys, the present research is focused on optimizing the composition of soluble phases, the structure and morphology of insoluble phases, and artificial ageing processes. The results show that the best matches, 0.4 wt% Mg and 1.2 wt% Cu in the Al–9Si alloy, avoided the toxic effect of the blocky Al2Cu on the mechanical properties of the alloy. The addition of 0.6 wt% Zn modified the morphology of eutectic Si from coarse particles to fine fibrous particles and the texture of Fe-rich phases from acicular β-Fe to blocky π-Fe in the Al–9Si–1.2Cu–0.4Mg-based alloy. With the optimization of the heat treatment parameters, the spherical eutectic Si and the fully fused β-Fe dramatically improved the ultimate tensile strength and elongation to fracture. Compared with the Al–9Si–1.2Cu–0.4Mg-based alloy, the 0.6 wt% Zn modified alloy not only increased the ultimate tensile strength and elongation to fracture of peak ageing but also reduced the time of peak ageing. The following improved combination of higher tensile strength and higher elongation was achieved for 0.6 wt% Zn modified alloy by double-stage ageing: 100 °C × 3 h + 180 °C × 7 h, with mechanical properties of ultimate tensile strength (UTS) of ~371 MPa, yield strength (YS) of ~291 MPa, and elongation to fracture (E%) of ~5.6%.


2021 ◽  
Vol 410 ◽  
pp. 197-202
Author(s):  
Pavel P. Poleckov ◽  
Olga A. Nikitenko ◽  
Alla S. Kuznetsova

This study considers the influence of various heat treatment conditions on the change of steel microstructure parameters, mechanical properties and cold resistance at a temperature of-60 °C. The common behavior of these properties is considered depending on the heating temperature used for quenching and subsequent tempering. Based on the obtained results, heat treatment conditions are proposed that provide a combination of a guaranteed yield point σ0.2 ≥600 N/mm2 with a low-temperature impact toughness KCV-60 ≥50 J/cm2 and plasticity δ5 ≥17%. The obtained research results are intended for industrial use at the mill "5000" site of MMK PJSC.


Alloy Digest ◽  
1969 ◽  
Vol 18 (2) ◽  

Abstract Berylco 33 25 is a free-machining beryllium copper alloy which has substantially the same mechanical properties and response to heat treatment as the standard Berylco 25, but which can be machined in 40 percent of the time. The alloy has high strength and hardness, a high fatigue strength, good resistance to corrosion and wear and good electrical conductivity. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-196. Producer or source: Kawecki Berylco Industries Inc..


2021 ◽  
Vol 410 ◽  
pp. 221-226
Author(s):  
Mikhail V. Maisuradze ◽  
Maxim A. Ryzhkov ◽  
Dmitriy I. Lebedev

The features of microstructure and mechanical properties of the aerospace high strength steel were studied after the implementation of various heat treatment modes: conventional oil quenching and tempering, quenching-partitioning, austempering. The dependence of the mechanical properties on the tempering temperature was determined. The basic patterns of the formation of mechanical properties during the implementation of isothermal heat treatment were considered. The optimal heat treatment conditions for the studied steel were established.


2010 ◽  
Vol 139-141 ◽  
pp. 157-162 ◽  
Author(s):  
Chin Chun Chang ◽  
Ji Gang Yang ◽  
Ling Qi ◽  
Chang Pin Chou

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.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2419 ◽  
Author(s):  
Alireza Dashti ◽  
Mohammad Shaeri ◽  
Reza Taghiabadi ◽  
Faramarz Djavanroodi ◽  
Farzaneh Vali Ghazvini ◽  
...  

In current research, the effect of the multi-directional forging (MDF) process on the microstructure, texture, mechanical and electrical properties of AA-6063 under different heat treatment conditions at various MDF temperatures was studied. The annealed AA-6063 alloy was processed up to three passes of MDF at ambient temperature. Three passes of this process were also applied to the solution-treated AA-6063 at ambient temperature and 177 °C. Microstructural investigations demonstrated that the MDF process led to a significant reduction in the average grain size as well as a considerable increase in the fraction of low angle grain boundaries. Texture analysis revealed that copper and Goss textures were mainly developed within the annealed and solution-treated samples of AA-6063, respectively. The hardness and shear strength values of all processed samples also showed a sizeable improvement compared to the initial heat-treated samples. For example, the hardness and shear yield strength value of the solution-treated sample MDFed for three passes showed more than 100 and 70% increase, respectively. The effect of the MDF process on the electrical conductivity of AA-6063 under different heat treatment conditions at various temperatures was negligible. So, it can be concluded that the MDF process increased the mechanical properties without an appreciable decrease in electrical conductivity.


2013 ◽  
Vol 58 (1) ◽  
pp. 127-132 ◽  
Author(s):  
B. Płonka ◽  
M. Lech-Grega ◽  
K. Remsak ◽  
P. Korczak ◽  
A. Kłyszewski

The object of this study was to develop parameter of the die forging process, such as feedstock temperature and to investigate her impact on the structure and mechanical properties of magnesium alloys in different heat treatment conditions. Tests were carried out on a 2,5MN maximum capacity vertical hydraulic press using forgings of sample (model) shapes. Then, based on the results obtained in previous work, research was carried out to develop for items forged from magnesium alloys the parameters of heat treatment to the T5 and T6 condition in the context of achieving possibly homogeneous and fine-grained structure and, consequently, high mechanical properties.


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