scholarly journals Natural and artificial ageing in aluminium alloys – the role of excess vacancies

2021 ◽  
pp. 117014
Author(s):  
Zi Yang ◽  
John Banhart
Keyword(s):  
Aluminium Alloys ◽  
Artificial Ageing

The Effect of Pre-Ageing and Addition of Copper on the Precipitation Behaviour in Al-Mg-Si Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 543-548 ◽  
Author(s):  
A.I. Morley ◽  
M.W. Zandbergen ◽  
Alfred Cerezo ◽  
George D.W. Smith
Keyword(s):  
Aluminium Alloys ◽  
Deleterious Effect ◽  
Atom Probe ◽  
Artificial Ageing ◽  
Strengthening Effect ◽  
Natural Ageing ◽  
Aged Material ◽  
3 Dimensional ◽  
Precipitation Behaviour ◽  
6Xxx Series

Hardness measurements and 3-dimensional atom probe analysis have been used to characterise the precipitation behaviour in two 6xxx series aluminium alloys, one Cu-free alloy (Al-0.78at%Mg- 0.68at%Si) and one Cu-containing alloy (Al-0.78at%Mg-0.68at%Si-0.30at%Cu). The heat treatments consisted of either natural ageing or pre-ageing at 353K followed by a paint-bake treatment at 453K. Natural ageing was seen to increase the hardness, and hence reduce formability compared to pre-ageing. In addition, the strengthening effect of artificial ageing was less after natural ageing than after pre-ageing. In the Cu-free alloy, needle-like β″ was observed to form only after a pre-ageing treatment during the first 60 minutes of a paint-bake treatment. In the Cucontaining alloy, needle-like β″ formed during paint bake in both the naturally-aged and pre-aged material, although it is formed more rapidly after pre-ageing. This was accompanied by an increase in strength over the Cu-free alloy and indicates that Cu reduces the deleterious effect of natural ageing.

scholarly journals Effect of pre-aging deformation on the intergranular corrosion resistance of 6000 series aluminium alloys

2020 ◽  
Vol 326 ◽  
pp. 04004
Author(s):  
Otto Lunder ◽  
Julie Grønvold ◽  
Calin Daniel Marioara ◽  
Sigurd Wenner ◽  
Trond Furu
Keyword(s):  
Grain Boundaries ◽  
Aluminium Alloys ◽  
Intergranular Corrosion ◽  
Thermomechanical Processing ◽  
Artificial Ageing ◽  
Transmission Electron ◽  
Cu Film ◽  
Scanning Transmission ◽  
Automotive Sheet ◽  
Nearly Continuous

Aluminium alloys in the 6000 series may become susceptible to intergranular corrosion (IGC) by unfavourable thermomechanical processing in combination with presence of Cu and a low Mg/Si ratio. The IGC susceptibility has been related to the segregation of Cu during artificial ageing to form a nearly continuous Cu film along the grain boundaries with an anodic solute depleted zone adjacent to it. In this work, extruded alloys 6005 and C28 as well as two variants of 6016 automotive sheet were subjected to various degrees of deformation by rolling or stretching before artificial aging. Accelerated IGC testing showed that pre-deformation significantly improved the IGC resistance of the Cu containing extruded alloys, while no improvement was observed for the 6016 sheet materials containing < 0.01 wt% Cu. High resolution scanning transmission electron microscopy (STEM) of pre-deformed 6005 alloy showed precipitation of Cu-containing Q' phase on dislocations. As a result, the amount of Cu available for diffusion to the grain boundaries is reduced, which might explain why a beneficial effect of pre-deformation on the IGC resistance was observed only for the Cu-containing materials.

scholarly journals The role of quench rate on the plastic flow and fracture of three aluminium alloys with different grain structure and texture

2020 ◽  
Vol 150 ◽  
pp. 103257 ◽  
Author(s):  
Bjørn Håkon Frodal ◽  
Emil Christiansen ◽  
Ole Runar Myhr ◽  
Odd Sture Hopperstad
Keyword(s):  
Plastic Flow ◽  
Aluminium Alloys ◽  
Grain Structure ◽  
Quench Rate

scholarly journals Incorporation of alloying elements into porous anodic films on aluminium alloys: The role of cell diameter

2019 ◽  
Vol 296 ◽  
pp. 783-789 ◽  
Author(s):  
J.M. Torrescano-Alvarez ◽  
M. Curioni ◽  
H. Habazaki ◽  
T. Hashimoto ◽  
P. Skeldon ◽  
...  
Keyword(s):  
Aluminium Alloys ◽  
Alloying Elements ◽  
Cell Diameter ◽  
Anodic Films

Effects of Natural Ageing on T6 Heat Treated Rheocasts of 319S Aluminum Alloy

2016 ◽  
Vol 256 ◽  
pp. 58-62 ◽  
Author(s):  
Kang Du ◽  
Qiang Zhu ◽  
Da Quan Li
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminium Alloys ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Solution Treatment Temperature ◽  
Artificial Ageing ◽  
Natural Ageing ◽  
T6 Heat Treatment ◽  
Semi Solid

T6 heat treatment is an effective method to improve the comprehensive properties of Al-Si-Cu-Mg series aluminium alloys. Solution treatment temperature and time, quench process and media, as well as artificial ageing temperature and time are the key factors to determine mechanical properties. Besides these factors, natural ageing, i.e. the holding time between quenching and the starting of artificial treatment at ambient temperature was observed to be significant affect mechanical properties of the aluminium alloys. This effect on semi solid processed aluminium alloys was lack of investigations as the semi solid process produces T6 treatable and weldable components. The present paper focuses on the change regularity of hardness and precipitate behaviour of semi-solid 319S aluminium alloy under different natural ageing (NA) treatment additional to standard T6. Density and morphology of hardening precipitates are analysed using TEM, and the influence mechanism of NA during T6 heat treatment will be discussed. The results show that NA has a positive influence on mechanical properties of the rheo-cast 319S alloy.

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