SGER: Laser Hardening of Aluminum Alloys

这项探索性研究的小额拨款将确定用一种新的准分子激光工艺对铝及其合金进行受控表面硬化的可行性。铝合金319广泛用于工业应用，但不具有许多耐磨应用所需的硬度。这种合金不能用常规方法硬化。该项目将研究通过高度控制的能量输入到暴露于氮环境的表面来创造氮化铝表面层的潜力。有几个冶金方面的问题使得这是一个高风险的努力。热激光上釉的早期工作提供了一些修改形式的铝的第一个证据。为了使工艺成功，必须形成氮化铝层，并且必须与铝相邻。这需要能量输入与冶金事件发生的热力学平衡。铝合金中的其他元素可以延缓氮化铝的形成，或限制硬层的厚度和/或完整性。如果能识别并保持对加工参数的适当控制，预计铝表面的硬度可提高12倍之多。铝合金的表面硬化在汽车和航空航天应用中是非常需要的，如果该工艺的可行性得到确立，则需要进一步研究适用范围、耐用性和适合激光硬化的合金范围。

This Small Grant for Exploratory Research will establish the feasibility of performing controlled surface hardening of aluminum and its alloys with a novel excimer laser process. Aluminum Alloy 319 is widely used in industrial applications, but does not have the hardness necessary for many wear resistant applications. This alloy cannot be hardened by conventional means. This project will investigate the potential for creating an aluminum nitride surface layer by highly controlled energy input to the surface which is exposed to a nitrogen environment. There are several metallurgical issues that make this a high risk endeavor. Early work in thermal laser glazing provided some of the first evidence of modified forms of aluminum. For the process to be successful, an aluminum nitride layer must form and must be contiguous with the aluminum. This requires thermodynamic balancing of the energy input with the metallurgical events taking place. Other elements in the aluminum alloy could retard the formation of the aluminum nitride, or limit the thickness and /or integrity of the hard layer. If the appropriate control of the processing parameters can be identified and maintained, it is expected that the hardness of the aluminum surface could be increased by as much as twelvefold. The surface hardening of aluminum alloys is highly desired for automotive and aerospace applications, and if the feasibility of the process is established, further research would need to be conducted into limits of applicability, durability, and range of alloys appropriate for laser hardening.