Analysis and characterization of microstructure, residual stress, and resultant in-service properties for production of inline-4 aluminum engine block

点击翻译按钮获取中文摘要

Minimization of engine weight often relies on the use of light alloys such as aluminum and magnesium, rather**than heavier alloys such as cast iron or steel. However, light alloys do not have as substantial elevated**temperature mechanical properties as do steel or iron. Therefore, while under elevated temperatures and high**loads during service, light alloys are often susceptible to permanent deformation or fracture. These material**failures may result in improper sealing of the combustion chamber, resulting in discharge of the air-fuel**mixture to the atmosphere, (known as blow-by). Even with minute amounts of blow-by occurring, the engine**efficiency drastically decreases, which results in increased fuel consumption and a rapid increase in hazardous**emissions. The resulted recalls would lead to significant financial losses for the automotive manufacture.**Therefore, it is important to study how the aluminum and iron lines interact in the new Ford engine blocks to**be able to optimize the manufacturing process (casting, heat treatment and machining). The results of this study**are critical to reduce or eliminate defects in the engine casting that may contribute to undesirable distortion,**low mechanical properties, and eliminate material cracking that may lead to blow-by or engine failure during**service. The objectives of this project include: (i) proper determination and quantification of the residual**stresses evolution during manufacturing. This will allow Ford Canada to identify and adjust the manufacturing**processes that may lead to high residual stresses, which contribute to component failure during service, and (ii)**to study how cast-in iron liners influence the local microstructure of the aluminum alloy. This will provide**Ford with critical information on how the material behaves during casting (cooling rates, coefficient of thermal**expansion mismatch, local alloy strength, microstructure, etc.). This work will provide information on how the**manufacturing process should be optimized to provide better alloy mechanical properties after casting and**post-casting heat treatment. Ultimately, this research looks to provide Ford Canada with a material and**manufacturing process for a new lighter engine block, enabling further increase in fuel efficiency.