Structure-environmental performance relationship studies of wrought mg alloys with an aim towards increasing their utilization in the transportation industries

通过使用轻质合金来减少汽车的总质量是可以实现提高燃料效率和减少有害排放的手段之一。镁合金部件具有高比强度和刚度，为实现这些目标提供了重要机会。然而，有两个主要的技术问题阻碍了变形镁合金产品的广泛应用，即相对低的生产率和具有高强度、高延展性和高耐腐蚀性的组合的新合金的开发。拟议的研究计划将制定战略，以提高耐腐蚀性，实现更好的理解和预测与锻造镁铝锌合金相关的环境退化。为此，本研究将表征和阐明（1）晶体取向对在非合金化单晶和多晶Mg上形成的准钝化膜的结构、组成和稳定性的影响，以及（2）金属间相的组成、尺寸和分布对多晶Mg-Al-Zn合金中的微电流活性的影响，作为合金含量的函数，以及热机械加工路线（板材、挤压件和锻件）。将利用微米级和纳米级分辨率探针技术的全面组合来实现这些目标。将使用高分辨率电子显微镜获得关于基质、金属间相和钝化膜的结构和组成信息，而将使用高分辨率扫描电化学探针技术（SKP和SVP）获得基质和金属间相的局部电化学活性。至少有三名HQP将接受本建议书的培训。除了帮助该行业实现燃油经济性、排放和性能方面的减重目标外，与HQP合作开发的技术还将创造加拿大的“专有技术”，有效支持国内供应商的创新努力。

Reducing the overall mass of automobiles by the use of lightweight alloys is one of the means by which improved fuel efficiency and reduced harmful emissions can be attained. Mg alloy components, with their high specific strength and stiffness, provide significant opportunities to achieve these goals. However, there are two major technological issues preventing widespread application of wrought Mg alloy products, namely the relatively low production rate and the development of new alloys with a combination of high strength, high ductility and high corrosion resistance. The proposed research program will develop strategies to improve the corrosion resistance by achieving an improved understanding and prediction of the environmental degradation associated with wrought Mg-Al-Zn alloys. To this end, the research will characterize and elucidate the influence of (1) crystallographic orientation on the structure, composition and stability of the quasi-passive film formed on unalloyed single crystal and polycrystalline Mg, and (2) composition, size & distribution of intermetallic phases on the micro-galvanic activity in polycrystalline Mg-Al-Zn alloys, as a function of the alloy content, and the thermomechanical processing route (sheet, extrusions and forgings). An encompassing combination of micro- and nano-scale resolution probe techniques will be utilized to achieve these goals. Structural and compositional information on the matrix, intermetallic phases and passive film will be obtained using high resolution electron microscopy, whereas the localized electrochemical activity of the matrix and intermetallic phases will be obtained using high resolution scanning electrochemical probe techniques (SKP and SVP). A minimum of three HQP will be trained in this proposal. In addition to helping the industry attain their weight reduction targets for fuel economy, emissions and performance, the technology developed with the HQP will create a Canadian "know-how" that will effectively support innovation efforts of domestic suppliers.