The 4032 aluminum Alloy (UNS A94032) is a 4000 series aluminum alloy that offers the highest tensile strength. It can be forged or welded using inert-gas arc welding. Machinability is fair to good, and we recommend lubricating the alloy during machining with an oil lubricant.

4032 aluminum is commonly used in the manufacturing of pistons. JE offers an extensive line of high-quality pistons in this alloy that are made to meet the needs of both performance and competition applications.

A higher silicon content allows this alloy to run with tighter cold-start clearances and quieter piston operation in cold climates. This makes it a great choice for street engine applications, especially if long-term ring groove wear is an issue.

Its reduced ductility does make it less resistant to cracking with extreme impact loads such as detonation or unforeseen physical contact than would be the case with a 2618 alloy. It is however still a good choice for performance and competition applications that require the highest strength possible while keeping the alloy’s overall ductility at a minimum.

SEM morphologies of unmodified and modified 4032 were analyzed with various Sr contents to determine the effect of Sr on the microstructure of the aluminum alloy. It was revealed that when 0.02 wt% Sr was added, the eutectic Si phase exhibited a large change in morphology from coarse acicular/flaky into a mixture of dendrites in some localized areas and a few fine fibers.

It is believed that the Sr addition could cause a dramatic shift in the growth dynamics of the Al4Sr phase, making the pseudoeutectic area move to zones above the extended line of the aluminum liquidus. Moreover, the number of primary Si phases was reduced and the eutectic point increased.