Development of manufacturing technologies and characterization of microstructure, residual stress, and resultant in-service properties for production of I6 aluminum cylinder block

I6 铝制气缸体生产的制造技术开发以及微观结构、残余应力和使用性能的表征

• 批准号: 516170-2017
• 负责人: Sediako, Dimitry
• 金额: $ 1.82万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=640390
• 关键词: Development; manufacturing; technologies; characterization; microstructure

Nemak Canada is currently introducing a new aluminum engine block into its product line that is based on I6architecture. This involves development of new casting technology, which shall address exceptionally thin wallsections, interbore cooling channels, and localized integrated chills. The focus of this research is themicrostructure, mechanical properties and residual stresses in an aluminum alloy engine block that have beenmanufactured with the new technology. Aluminum alloys do not have as high mechanical strength and wearresistance as compared to, for example, ferrous alloys and are often susceptible to deformation or distortionduring service while under high loads and elevated temperatures, and excessive wear at friction surfaces. Thispermanent deformation and excessive wear can lead to improper sealing of the combustion chamber, whichwill result in leakage of the air-fuel mixture past the piston rings into the crankcase, known as blow-by. Withthe occurrence of any amount of blow-by, the engine efficiency decreases and fuel consumption and carbon andNOx emissions rapidly increase. Due to strict environmental laws now commonly enforced in mostjurisdictions, engines suffering from blow-by would require expensive recalls, resulting in significant financiallosses for the automotive industry. Mechanical properties are highly dependent on alloy composition andmicrostructure. To secure the engine block quality is it therefore important to understand how microstructureand residual stress evolve at each stage of the manufacturing process (casting, heat treatment, and machining).The first objective of this research is to analyze the microstructure and residual stresses for each stage of themanufacturing process. This will allow to identify the stage(s) during manufacturing that may lead todetrimental microstructural changes or high residual stresses that contribute to component premature failureduring service. The second objective is to study how cast-in chills influence the post casting heat treatment.This will enable optimization of the casting and heat treatment process to enhance alloy mechanical propertiesand thus provide OEMs a new lighter material for engine blocks that will increase automobile fuel efficiency.

Nemak Canada目前正在将一种基于I6架构的新型铝发动机缸体引入其产品线。这涉及到新铸造技术的开发，这将解决异常薄壁部分，内孔冷却通道，和局部集成冷铁。本文主要研究了采用新工艺制造的铝合金发动机缸体的显微组织、力学性能和残余应力。与例如铁合金相比，铝合金不具有高的机械强度和耐磨性，并且在高载荷和高温下的使用期间经常容易变形或扭曲，并且在摩擦表面处过度磨损。这种永久变形和过度磨损会导致燃烧室密封不当，从而导致空气燃料混合物通过活塞环泄漏到曲轴箱中，称为漏气。随着任何量的漏气的发生，发动机效率降低，燃料消耗以及碳和NOx排放迅速增加。由于大多数司法管辖区目前普遍执行严格的环境法，发生漏气的发动机将需要昂贵的召回，从而导致汽车行业的重大财务损失。机械性能高度依赖于合金成分和显微组织。为了保证发动机缸体的质量，了解制造过程中各个阶段（铸造、热处理和机加工）的显微组织和残余应力是如何演变的是很重要的，本研究的第一个目标是分析制造过程中各个阶段的显微组织和残余应力。这将允许识别制造过程中可能导致有害的微观结构变化或高残余应力的阶段，这些阶段会导致部件在使用过程中过早失效。第二个目标是研究镶铸冷铁对铸后热处理的影响，这将优化铸造和热处理工艺，以提高合金的机械性能，从而为原始设备制造商提供一种新的更轻的发动机缸体材料，提高汽车燃油效率。