Cost-effective lightweight complex-shaped structural components made of magnesium: A hybrid manufacturing paradigm

汽车行业正在经历重大转变，在车辆设计中使用轻质材料，以提高燃油/动力经济性。镁（Mg）具有密度低、密度约为铝的三分之二、比强度高和良好的疲劳性能等特点，近年来受到了广泛的关注。然而，由于镁在室温下的成形性能有限，其在汽车结构件中的应用受到了限制。铸造和锻造已被考虑用于制造疲劳关键零件，例如转向和悬架部件。铸造能够以相对较低的成本制造复杂形状，但可能会导致缺陷和机械性能较差。另一方面，锻造提供了优异的机械性能，但仅限于简单的形状，或者需要多阶段锻造并在阶段之间进行飞边修整。为了利用铸造的成本效益和锻造零件的优越材料性能，本研究提出了一种新型混合铸造然后锻造镁合金。在这种独特的方法中，零件首先被铸造成具有工程材料分布的最佳中间形状，然后在接近再结晶温度下锻造成最终形状。这项研究的总体目标是科学地理解铸件的初始材料分布和性能对锻造过程中微观结构和织构演变及其最终性能的影响。这项研究将开发科学知识和支持技术，用于制造汽车应用的镁复杂形状结构部件。

Automotive industries are going through a major shift in using lightweight materials in vehicle design considerations to improve fuel/power economy. Magnesium (Mg) with low density, approximately two-thirds as dense as aluminum, high specific strength, and good fatigue properties, has received significant attention in the recent years. However, due to limited formability of Mg at room temperature, its application to automotive structural components has been limited. Casting and forging have been considered for manufacturing of fatigue-critical parts such as steering and suspension components. Casting enables manufacturing of complex shape at relatively low cost but can result in defects and poor mechanical properties. On the other hand, forging provides excellent mechanical properties but is limited to simple shapes, or requires multiple stage forging with flash trimming in between stages. To leverage the cost-effectiveness of casting and superior material properties of forged parts, a novel hybrid cast followed by forging of Mg alloys is proposed in this research. In this unique method the part is first cast to an optimum intermediate shape with engineered material distribution and then forged into its final shape at near re-crystallization temperature. The overall objective of this research is to develop a scientific understanding of the impact of the initial material distribution and properties of cast on the microstructure and texture evolution during the forging process and its final properties. This research will develop the scientific knowledge and enabling technologies that will be used to manufacture Mg complex-shaped structural parts for automotive applications.