SGER: Laser Hardening of Aluminum Alloys

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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.