Influence of Quench Rate on the Artificial Ageing Response of an Al-8Si-0.4Mg Cast Alloy
2015 (English)In: Materials Science Forum, ISSN 0255-5476, Vol. 828-829, 219-225 p.Article in journal (Refereed) Published
The aim of the study is to present the influence of quench rate on the artificial ageing response of Al-8%Si-0.4%Mg cast alloy in terms of Brinell hardness and yield strength. The investigated material was produced by a gradient solidification technique and exhibited a microstructure that corresponds to the one of gravity die castings, with a dendrite arm spacing of approximately 25 μm. The study comprises two solution treatment temperatures, five quench rates and artificial ageingtimes exceeding 100 hours at 170 and 220 ⁰C. The microstructure and concentration profiles of Mgand Si were evaluated using energy and wavelength dispersive spectroscopy. Microstructural examination reveals an increment of solutes in the Al-matrix when higher solution treatment temperatures accompanied with high quench rates are applied and shows how both Si and Mgatoms have diffused towards the eutectic during quenching. Consequently, i.e. by increasing the levels of solutes and vacancies, the highest strength levels were realized. The study confirmed that quench rates above 2 ⁰C /s do not offer substantial strength improvement while quenching at lower rates resulted in a lower peak hardness and longer times to peak.
Place, publisher, year, edition, pages
2015. Vol. 828-829, 219-225 p.
Al-Si cast alloys, Solution heat treatment, Quench rates, Ageing, Hardness
IdentifiersURN: urn:nbn:se:hj:diva-27142Local ID: JTHMaterialISOAI: oai:DiVA.org:hj-27142DiVA: diva2:820408