Evaluation of a New High Pressure Diecast Magnesium Alloy with Improved Ductility for Self-Piercing Riveting (SPR) Performance

交通运输部门不断增长的二氧化碳排放量占加拿大温室气体排放量的25% **，政府的目标是到2050年减少45-65%。车辆重量每减轻10%，燃油经济性可达8%**，每减轻一公斤车辆重量，二氧化碳排放量可减少约20公斤。汽车行业**占加拿大制造业国内生产总值（GDP）的12%以上，提供超过55万个就业岗位。**汽车零部件的创新对于这个全球化和高度竞争的行业具有战略重要性。**在镁（Mg）汽车零部件行业创造专业知识和技术基础，对于**加拿大的全球竞争非常重要，可以维持目前的水平，并使未来的电动、燃料电池、**和混合动力汽车技术成为可能，为创造新的就业机会和环境可持续性创造机会。**子午线轻量化技术（MLT）是世界上最大的轻量化镁合金压铸件供应商，**为全球三大洲的大多数汽车制造商提供服务。为了开发一种新的Mg应用，**该组织迫切需要一种新的镁合金，这种合金可以通过自穿孔铆接(SPR)**技术进行紧固。当Mg为下一层时，SPR在Mg异种金属接头中表现出明显的挑战。**MLT考虑到2017-18年控制镁合金SPR性能的主要因素是拉伸延展性，与麦吉尔大学的M. Pekguleryuz教授进行了NSERC合作，并开发了一种新的镁合金**，其延展性比商用合金AM50A高14%，具有更好的拉伸强度和耐腐蚀性。**这些性能使新型镁合金对开发新的汽车应用非常感兴趣。压铸合金的发展是相当具有挑战性的。由于商用压铸机通常用于铸造大型零件，因此Mg合金开发的早期阶段通常是在永久模具样品上进行的，就像我们最初的Engage项目一样。MLT使用压铸来生产他们的汽车零件。由于**铸造工艺对镁合金的性能（强度、延展性、耐腐蚀性）有影响，在**拟建项目中，将针对压铸工艺对新合金进行优化和开发。

Growing CO2 emissions from the transportation sector contribute 25% of Canada's greenhouse gas emissions**in which the government has targeted 45-65% reduction by 2050. A 10% saving in vehicle weight leads to ~8%**fuel economy and ~20 kg reduced CO2 emissions per kg of vehicle weight reduced. The automotive sector**contributes over 12% of Canada's manufacturing Gross Domestic Product (GDP) with more than 550,000 jobs.**Innovation in vehicle components is of strategic importance for this global & highly competitive industry.**Creating expertise and a technology-base in the magnesium (Mg) automotive parts industry is important for**Canada's global competition, to sustain the current level and to enable future technologies of electric, fuel cell,**and hybrid powered vehicles creating opportunities for new job creation, and environmental sustainability.**Meridian Lightweight Technologies (MLT) is the largest supplier of lightweight Mg die castings in the world,**serving most of the global automotive manufacturers on three continents. To develop a new Mg application,**the organization urgently needs a new Mg alloy which can be fastened by Self-Piercing Riveting (SPR)**technology. SPR exhibits significant challenges in Mg dissimilar metal joints when Mg is the lower layer.**MLT considering the main factors governing the SPR performance of Mg alloys to be tensile ductility in**2017-18, conducted an NSERC Engage with Prof. M. Pekguleryuz (McGill) and developed a new Mg alloy**with 14% higher ductility, better tensile strength & corrosion resistance than the commercial alloy AM50A.**These properties make the new Mg alloy highly interesting for developing new automotive applications. The**development of diecasting alloys is rather challenging. Since commercial diecasting machines are usually made**for casting large parts, early phases of Mg alloy development are customarily conducted on permanent mold**samples, as was in our initial Engage project. MLT uses diecasting to produce their automotive parts. Since the**casting processes have impact on the properties (strength, ductility, corrosion resistance) of Mg alloys, in the**proposed project, the new alloy will be optimized and developed for the diecasting process.