Effects of Heat Treatment on the Microstructure and Hardness of A356 (AlSi7Mg0.3) Manufactured by Vertical Centrifugal Casting

• Published in: Applied sciences Vol. 11; no. 23; p. 11572
• Main Authors: Kim, Wonho, Jang, Kyungsu, Ji, Changwook, Lee, Eunkyung
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.12.2021
• Subjects: A356 alloys; Aging; Alloys; Aluminum alloys; Annealing; Atoms & subatomic particles; Automotive parts; Brake disks; Casting alloys; Centrifugal casting; Cooling; Corrosion resistance; Driving ability; Guinier Preston zone; Hardness; Heat treatment; Heat treatments; Intermetallic compounds; Mechanical properties; microstructure; Solid solutions; Solution heat treatment; Steel pipes; Tensile strength; Velocity; Water quenching; Weight reduction; Japan
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app112311572

The A356 alloy has been widely used in automotive components, such as wheels and brake disks, because it is an excellent lightweight material with high corrosion resistance and good mechanical properties. Recently, to reduce the weight of brake disks, the Fe-A356 hybrid brake disk has been suggested. Because brake disk quality is directly related to driving safety, the T4/T6 heat treatment of centrifugally cast A356 alloys were performed to enhance the mechanical properties and reduce micro-segregation. The solid-solution heat treatment followed by annealing caused the formation of Mg-rich intermetallic compounds on the grain boundaries of the Al matrix, decreasing the average hardness of the alloys by 13 HV. In contrast, the solid solution followed by water quenching (T4) reduced the area fractions of the intermetallic compounds and increased the average hardness by 11 HV. The T6 heat-treated A356 alloys, which were influenced by the formation of the Guinier–Preston zone exhibited a relatively higher average hardness, by 18 HV, compared to T4 heat-treated A356 alloys.