scholarly journals Effect of Cooling Rate from Solution Treatment on Precipitation Behavior and Mechanical Properties of Alloy 706

Author(s):  
T. Shibata ◽  
T. Takahashi ◽  
Y. Shudo ◽  
M. Kusuhashi ◽  
J. Taira ◽  
...  
Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1350
Author(s):  
Sui Wang ◽  
Yake Wu ◽  
Tengyu Zhang ◽  
Feng Jiang

Microstructure and property evolution of a powder-forged Fe-2.5Cu-C alloy during continuous cooling and subsequent aging were investigated to improve its mechanical properties. During continuous cooling, copper precipitates formed were consistent with the interphase mechanism when the cooling rate was less than 7 °C/s; however, the hardness of the specimen was always higher at faster cooling rates because finer grains and harder phases formed. During subsequent aging, copper precipitates formed and/or coarsened continuously while the hardness of the alloys was greatly influenced by the combined effects of the primary and secondary precipitates, as revealed by the theoretical calculations. In addition, the forming and evolving mechanisms of the copper precipitates at different stages were also discussed based on the experimental results. This study will provide guidance to the industry for achieving high performance in the powder-forged products by treatment manipulation.


2016 ◽  
Vol 849 ◽  
pp. 570-579
Author(s):  
Qiang Huang ◽  
Jin Xia Song ◽  
Qing Li ◽  
Wei Peng Ren ◽  
Xin Guang Guan ◽  
...  

The microstructures and mechanical properties of superalloy K465 under different heat treatment, including as as-cast, solution treatment and aging, were investigated. The results showed that γ' precipitates in as-cast condition exhibited two kinds of morphologies of fine regular cuboidal shape at dendritic arm and coarse irregular form in interdendritic region. MC carbides decomposed into M6C carbides partly after 1210°C/4h solution treatment. The high temperature stress-rupture life can be improved obviously with the increasing cooling rate. When cooling rate was lower than 70°C/min, the room temperature tensile elongation increased with cooling rate increasing. When cooling rate was higher than 90°C/min the room temperature tensile elongation decreased with cooling rate increasing. The proper cooling rate of 70oC/min~90oC/min is advantageous for the achievement of excellent comprehensive properties. When aging treatments continued the regularization of γ' resulted in the improvement of stress-rupture life and the reduction of tensile elongation. The mechanical property gap between the solution treatment and aging can be decreased with increasing cooling rate.


Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5037
Author(s):  
Tao Ma ◽  
Sicong Zhao ◽  
Liping Wang ◽  
Zhiwei Wang ◽  
Erjun Guo ◽  
...  

The effect of solution treatment time on the microstructure and mechanical properties of aged the Mg-2.0Nd-2.0Sm-0.4Zn-0.4Zr (wt.%) alloy were investigated to give full play to the performance of the alloy. As the solution treatment time increased from 2 h to 12 h at 788 K, the grain size of the solution-treated alloy significantly increased, and the network-like β-Mg12(Nd, Sm, Zn) phase gradually dissolved into the α-Mg matrix. It should be noted that no obvious residual β phase can be observed when the solution treatment time was more than 8 h. After the solution-treated alloy was further aged at 473 K for 18 h, a large number of nanoscale precipitates were observed in the α-Mg matrix. The solution treatment time was 2 h, the α-Mg matrix mainly consisted of spherical-shaped and basal plate-shaped precipitates. Upon the increase of solution treatment time to 8 h, the key strengthening phases transformed from spherical-shaped precipitates and basal plate-shaped precipitates to prismatic plate-shaped β′ precipitates. The orientation relationship between β′ precipitates and α-Mg matrix was (1¯10)β′ // (11¯00)α and [112]β′ // the [224¯3]α. Further increasing of solution treatment time from 8 h to 12 h, the key strengthening phases mainly were still β′ precipitates. The solution treatment of aged alloy was carried out at 788 K for 8 h, which achieved optimal ultimate tensile strength (UTS) of 261 ± 4.1 MPa, yield strength (YS) of 154 ± 1.5 MPa, and elongation of 5.8 ± 0.1%, respectively.


2019 ◽  
Vol 38 (2019) ◽  
pp. 113-124 ◽  
Author(s):  
Yaxu Zheng ◽  
Fuming Wang ◽  
Changrong Li ◽  
Yu Lin ◽  
Ruifang Cao

AbstractThe effect of cooling rate on martensitic structure and carbides precipitation behavior was investigated based on Cr-Mo alloy steel with different quenching media of oil, water and 10% NaCl-water, respectively. The influence mechanism of martensite structure and carbide precipitates on mechanical properties was also studied. The results showed that martensite packets and blocks were refined with water quenching, however, they were coarse with oil or 10% NaCl-water quenching. Martensite laths were refined and dislocation density increased with increasing cooling rate. The carbides in tempered steel were coarse obviously with 10% NaCl-water quenching. The impact toughness deteriorated significantly with 10% NaCl-water quenching due to coarsening of martensite structure and carbides.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2591 ◽  
Author(s):  
Yong Li ◽  
Guanjun Gao ◽  
Zhaodong Wang ◽  
Hongshuang Di ◽  
Jiadong Li ◽  
...  

Aluminum alloys are widely used as first-choice materials for lightweight automotive applications. It is important that an alloy have a balance between strength and formability. In this study, the alloys were melted, cast, hot rolled, and cold rolled into 1 mm-thick sheets. The microstructure, mechanical properties, and precipitation behavior of Al–Mg–Si–1.0 wt %-Zn alloys with Mg/Si ratios of 0.5, 1, and 2 after solution treatment were studied using optical and electron microscopy, a tensile test, the Vickers hardness test, and differential scanning calorimetry. The results showed that a high density and number of Al–Fe–Si particles were observed in the matrix, thus causing the formation of more homogeneous and smaller recrystallized grains after treatment with the solution. In addition, a higher volume fraction of cubeND and P-types texture components formed during solution treatment. Also, a high r value and excellent deep drawability were achieved in the medium-Mg/Si-ratio alloy. The formation of denser strengthening precipitates led to a better paint-bake hardening effect in comparison with the other two alloys. Furthermore, the precipitation kinetics were enhanced by the addition of Si, and the addition of Zn did not alter the precipitation sequence of the Al–Mg–Si alloy. The dual-phase strengthening effect was not achieved in the studied alloys during paint-bake treatment at 175 °C.


2011 ◽  
Vol 194-196 ◽  
pp. 1225-1230
Author(s):  
Chang Chun Yang ◽  
Yong Lin Kang ◽  
Sheng Qin ◽  
Li Xin Wang

The effect of solution treatment from 1050°C to 1200°C, soaking time 15min on microstructure, mechanical properties and precipitation behavior of Cr20Ni32AlTi alloy was investigated. The results are as follows: with the increasing of the solution treatment temperature from 1050°C to 1200°C, the average grain size increases remarkably from 17μm to 110μm, the strength of alloy decreases while the elongation increases. The amount of carbide precipitation in the alloy decreases with the increasing of solid solution temperature. The optimum solution treatment temperature for the investigated Cr20Ni32AlTi alloy is 1150°C~1200°C.


Sign in / Sign up

Export Citation Format

Share Document