Heat Treatment Practice of Wrought Age-Hardenable Aluminum Alloys

2018 ◽  
pp. 462-477
2007 ◽  
Vol 26-28 ◽  
pp. 531-534
Author(s):  
B.M. Moon ◽  
Bong Hwan Kim ◽  
Je Sik Shin ◽  
Sang Mok Lee

For thin-walled casting development of austempered ductile iron (ADI), permanent mold casting and accompanied heat treatment practice were systematically investigated to suppress and/or remove chill defects of ductile cast iron (DCI) with various thickness of 2 to 9 mm and to ensure mechanical properties of the final ADI casting. Si content was increased up to 3.8% to reduce the chill formation tendency under a high cooling rate. The residual Mg content remarkably affected the nodule count, while the nodule size and spherodization were proven to have weak relationships. Austenitizing process followed by austempering was very sensitive to chemical compositions (Si and Sn) and heat treatment temperature. As a practical application, the steel bar coupler for a structural frame was tried to produce without subsequent machining.


2006 ◽  
Vol 114 ◽  
pp. 91-96 ◽  
Author(s):  
Maxim Yu. Murashkin ◽  
M.V. Markushev ◽  
Julia Ivanisenko ◽  
Ruslan Valiev

The effects of equal channel angular pressing (ECAP), further heat treatment and rolling on the structure and room temperature mechanical properties of the commercial aluminum alloys 6061 (Al-0.9Mg-0.7Si) and 1560 (Al-6.5Mg-0.6Mn) were investigated. It has been shown that the strength of the alloys after ECAP is higher than that achieved after conventional processing. Prior ECAP solution treatment and post-ECAP ageing can additionally increase the strength of the 6061 alloy. Under optimal ageing conditions a yield strength (YS) of 434 MPa and am ultimate tensile strength (UTS) of 470 MPa were obtained for the alloy. Additional cold rolling leads to a YS and UTS of 475 and 500 MPa with 8% elongation. It was found that the post-ECAP isothermal rolling of the 1560 alloy resulted in the formation of a nano-fibred structure and a tensile strength (YS = 540 MPa and UTS = 635 MPa) that has never previously been observed in commercial non-heat treatable alloys.


Author(s):  
Wellington da Silva Mattos ◽  
George Edward Totten ◽  
Lauralice de Campos Franceschini Canale

This article describes the concept of uphill quenching process applied in the heat treatment of aluminum alloys. Uphill quenching is interesting since residual stress reductions of up to 80% has been reported. In addition, substantial improvements in dimensional stability have been achieved for several types of aluminum parts. Often, uphill quenching is applied after quenching and before aging during the heat treatment of aluminum alloys. The uphill quenching process consists of the immersion of the part in a cryogenic environment, and after homogenization of the temperature, the part is transferred to the hot steam chamber to obtain a temperature gradient that will maintain the mechanical properties gained with this process. The results obtained are lower residual stress and better dimensional stability. The aim of this article is to provide a review of this process and to compare it with conventional heat treatment.


Author(s):  
V. Anil Kumar ◽  
S. Arjun ◽  
R.K. Gupta ◽  
P.V. Venkitakrishnan

Retrogression and re-aging (RRA) treatment was introduced to increase the stress corrosion cracking (SCC) resistance while retaining the strength attainable in T6 (peak aged) temper. Retrogression is a short-term heat treatment at an elevated temperature wherein a partial dissolution of metastable precipitates occurs, which are responsible for the hardening. During the next step, the material is re-aged in the regime of typical age hardening parameters to restore the strength with improved ductility. Response of RRA treatment has been reported on AA7XXX series Aluminum alloys such as AA7075, AA7050, AA7150, AA7049, and AA7010. Studies have been done on the effect of RRA on microstructure, mechanical properties such as tensile and hardness, corrosion, exfoliation corrosion, and SCC resistance by various researchers. The key characteristic of RRA is retrogression, which makes the re-precipitation in the matrix and coarsening of grain boundary precipitates such as MgZn2, η′. The retrogression treatment however requires high temperature and a short time, which limits the industrial application of RRA, especially in the heat treatment of the components with large cross section, due to the inherent thermal conductivity limitations. Hence, further work needs to be done in this area to apply this specialized heat treatment for industrial applications. This article brings out a comprehension of the changes in microstructure, tensile properties, and corrosion resistance of the various commonly used AA7XXX Aluminum alloys in structural applications with RRA heat treatment. The future scope of the work in RRA heat treatment is also discussed in this article.


2012 ◽  
Vol 32 ◽  
pp. 1139-1146 ◽  
Author(s):  
W. Boonchouytan ◽  
T. Ratanawilai ◽  
P. Muangjunburee

2007 ◽  
pp. 183-245 ◽  
Author(s):  
Vadim S. Zolotorevsky ◽  
Nikolai A. Belov ◽  
Michael V. Glazoff

2018 ◽  
Vol 734 ◽  
pp. 299-310 ◽  
Author(s):  
L.F. Wang ◽  
J. Sun ◽  
X.L. Yu ◽  
Y. Shi ◽  
X.G. Zhu ◽  
...  

2019 ◽  
Vol 950 ◽  
pp. 75-79
Author(s):  
Zhen Hai Xu ◽  
Chao Ran Ding ◽  
De Bin Shan

With the ever-increasing concern about the energy and environment crises, aluminum alloys are becoming increasingly desirable in the automotive, aerospace, construction and other related industries due to their high specific strength. Various heat-treatment–stamping integrated techniques have been invented to address the formability challenge of aluminum alloy sheets. Electric field affects the heat treatment process of aluminum alloys. In this paper, a device for application of electric field during the heat treatment was developed. The maximum dimensions of specimen are determined via observing the distortion of metal sheets after quenching in cool water. The high-temperature resistant pure nickel wire gains a high-voltage proof performance by wearing bowl-shaped porcelain tubes, and is used to connect electrodes to power supply. The high-voltage resistant mica plates are bolted together to fill the gap between the specimen and electrode. This device was then used in a common commercial furnace to study the effect of electric field applied during the heat treatment on mechanical properties of AA 6082 sheets. It is found that electric field could enhance mechanical properties of AA 6082. The application of electric field has a potential to lower the cost of heat-treatment–stamping integrated techniques.


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