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Feasibility study on contact heating warm forming of 7075-T6 aluminum alloy

Sun Lu, Zhang Zhiqiang, Song Zhenkun, Ren Mingwen, Jia Hongjie

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e209, 2023

EN

7075 aluminum alloy is becoming an ideal material for the manufacture of vehicle body parts due to the demands for energy-saving and lighter vehicles. To solve the problem that the strength of 7075-T6 aluminum alloy decreases due to over-aging after warm forming, contact heating warm forming (CHWF) technology was proposed in this work. Contact heating is a fast and efficient heating method that can make the blank reach the target temperature in a very short time. In this work, the effect of contact heating on the mechanical properties and microstructures of 7075-T6 aluminum alloy after warm forming and paint-baking (PB) was studied. It only took about 11.5 s to heat the 2 mm 7075 aluminum alloy sheet to 200 ℃ by contact heating, and the strength and the hardness of the formed parts could reach 94% and 92.5% of T6 condition, respectively. In contrast, the heating furnace needed 690 s to heat the sheet to 200 °C, and the strength and the hardness of the formed parts were 87% and 85.4% of T6 condition, respectively. Due to the fast heating rate of contact heating (17.5 ℃/s), the atoms and vacancies in the matrix did not have time to undergo diffusion and aggregation, so that the precipitates could not coarsen obviously. As a result, most of the η' precipitates in the T6 condition were retained. However, long-term heating in the furnace led to the transformation of η' precipitates into coarse η phase and the loss of strength and hardness.

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Deposition and Analysis of DLC Thin Films Obtained on 7075 Aluminum Alloy

Kuffova M., Marton M., Kottfer D., Rehak F.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2017

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Vol. 8, Nr 3 (29)

33--42

EN

In this study a-C:H (hydrogenated amorphous carbon) thin films were deposited on the 7075 Al alloy without and with admixture gas (N2) using a DC CVD (direct current chemical vapor deposition) method. The structural and mechanical properties were analyzed using Raman spectroscopy, SEM and nanoindentation. We obtained hardness of a-C:H thin film without and with N2 equal to 27.3 GPa and 21.4 GPa, respectively. Values of the Young’s modulus were equal to 135.5 GPa and 205.2 GPa, respectively.

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Czynniki kształtu w określaniu siły wyciskania profili ze stopu aluminium 7075

Pawłowska B.

Hutnik, Wiadomości Hutnicze

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2014

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Vol. 81, nr 7

492--497

PL

W artykule przedstawiono propozycje modyfikacji formuł analitycznych, pozwalających określić poziom siły kształtowania dla przypadku wyciskania profili o złożonej geometrii ze stopu 7075. Zaproponowana modyfikacja opiera się na wprowadzeniu do relacji analitycznej tzw. czynnika kształtu, dobranego odpowiednio do typu określonej grupy kształtowników. Uzyskane wyniki porównano z wartościami siły wyciskania otrzymanymi podczas badań eksperymentalnych, co pozwoliło na określenie wzorów oraz współczynników kształtu, które najlepiej przybliżają rzeczywisty proces.

EN

The paper presents the proposals of modification of analytic relationships which enable to asses of extrusion load for case of complexity extrudate cross-section of 7075 aluminum alloy. The proposed modification is based on introducting “shape factor” to analytic relationship according to special selection for definited groups of the shapes. The obtained results were compared with the values of the extrusion load received in the experimental work.