The effect of hot form quench (HFQ®) conditions on precipitation and mechanical properties of aluminium alloys

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:761

Article

Zheng, Kailun¹  Dong, Yangchun²  Zheng, Jing-Hua¹  Foster, Alistair³  Lin, Jianguo¹  Dong, Hanshan²  Dean, Trevor A.⁴ 

[1] Imperial Coll London, Dept Mech Engn, London SW7 2AZ, England

[2] Univ Birmingham, Sch Met & Mat, Birmingham B15 2TT, W Midlands, England

[3] Impress Technol Ltd, Unit E, Lyons Pk,46 Sayer Dr, Coventry CV5 9PF, W Midlands, England

[4] Univ Birmingham, Dept Mech Engn, Birmingham B15 2TT, W Midlands, England

关键词: Hot form quench (HFQ (R));    Blank transfer;    Mechanical property;    Hot deformation;    Precipitate;    7075;   

DOI  :  10.1016/j.msea.2019.06.027

来源: Elsevier

【 摘 要 】

Hot form Quench (HFQ (R)) represents a leading-edge hot sheet stamping technology for manufacturing complex-shaped high strength aluminium alloy panel components. Transfer of sheet blank from the furnace to the press is the first crucial step in the process. This paper reports work in which the effects of the blank transfer on the deformation of material during pressing and on the final properties after ageing through thermal-mechanical testing and microstructural observations. Two aluminium alloys are investigated, 6082 and 7075. Hardness, quasi-static uniaxial tensile measurements and TEM microstructure observations provide evidence that post-treatment properties and the underlying microstructure are strongly influenced by the blank transfer step. Severe deterioration in the post-treatment strength was observed for blank transfer temperature, ranging from 250 degrees C to 400 degrees C. The temperature-time-property (TTP) diagrams showed that 350 degrees C was the most sensitive temperature that reduced the post-treatment strength by 45% within 10 s holding. As evidenced by TEM, typical coarse eta and S precipitates at high temperatures were identified, which resulted in different post-treatment properties and hot deformation behavior. Finally, the results from HFQ (R) technology processed aluminium alloys 7075 and 6082 were compared with conventional TTP diagrams, enabling comparison with conventional scientific understanding of quenching effects.

【 授权许可】

Free