Thermodynamic modeling and experimental investigation of glass-forming magnesium alloys

开发包含所有可能的合金元素的可靠Mg数据库是申请人的长期目标。这将通过计算热力学结合关键实验，使用DSC，XRD，SEM/EPMA和扩散偶技术来实现。事实证明，这减少了建立这样一个多成分数据库所需的时间和精力。目前的建议集中在调查镁三元系统，具有很强的潜力，金属玻璃的应用。这类系统中的三种是Mg-Al-Y、Mg-Ni-Y和Mg-Cu-Y。镁基玻璃形成合金由于其低密度、高强度、优异的耐腐蚀性和高韧性而受到特别的关注。Mg基金属玻璃具有高的拉伸断裂强度，其是常规Mg基晶体合金的最高强度的两倍以上。更重要的是，在文献中提到，镁基合金具有产生最大块体金属玻璃的潜力。通过添加不同的合金元素来改善镁基合金的玻璃形成能力是目前国内外研究的重点。目前的建议旨在通过提供一个自洽的热力学数据库，可用于确定具有最高玻璃形成能力的镁合金的最有前途的组合物，以促进这些努力。与目前的试错法不同，在拟议的研究中，将使用该数据库识别有形成大块金属玻璃趋势的成分。这可以通过识别表现出低液相线表面的组合物来获得。值得注意的是，这种策略将提高获得最适合大块金属玻璃应用的镁基合金的机会，而不是传统的经验试错实验。此外，所提出的策略将能够预测玻璃形成能力的组合物敏感性，这是不可能的，通过现有的标准，是基于原子尺寸分布。该项目将使加拿大汽车和航空航天工业受益，并将为所有镁产品生产商提供新的机会。

Development of a reliable Mg database that contains all the possible alloying elements is the applicant's long term objective. This will be achieved through computational thermodynamics coupled with key experiments using DSC, XRD, SEM/EPMA and diffusion-couples techniques. This proved to reduce the time and effort necessary to establish such a multicomponent database. The current proposal focuses on investigating Mg ternary systems that have strong potential for metallic glass applications. Three of such systems are Mg-Al-Y, Mg-Ni-Y and Mg-Cu-Y. Mg-based glass-forming alloys have attracted special attention due to their low-density, high strength, excellent corrosion resistance, and high toughness. Mg-based metallic glasses exhibit high tensile fracture strength which is more than twice as high as the highest strength of conventional Mg-based crystalline alloys. More importantly, it is mentioned in the literature that Mg-based alloys have the potential to produce the largest bulk metallic glass. So far, the efforts worldwide are focussed on the improvement of the glass-forming ability of Mg-based alloys by additions of different alloying elements. The current proposal aims at contributing to these efforts by providing a self-consistent thermodynamic database that can be used to identify the most promising compositions for Mg-alloys that have the highest glass-forming ability. Unlike the current practice of trial and error method, in the proposed research, the compositions that have the tendency to form bulk metallic glasses will be identified using this database. This can be obtained through identifying the compositions that exhibit low lying liquidus surface. It is worth noting that this strategy will enhance the chance of obtaining the most suitable Mg-based alloys for bulk metallic glass applications instead of the traditional empirical trial and error experimentation. Further, the proposed strategy will enable predicting the composition sensitivity of the glass-forming ability which is not possible by the existing criteria that are based on atomic size distribution. This project will benefit Canadian automobile and aerospace industries and will provide new opportunities to all Mg products producers.