Laser surface alloying of aluminum and surface melting of Al-12Si-4Cu-1.2Mn alloy

Abstract

Aluminum alloys are groups of nonferrous metals finding a wide range of applications. They have appreciable properties such as high strength to weight ratio, high thermal conductivity, excellent corrosion resistance and workability. This favors their high demand in many industries. Aluminum is used in many applications―automobile parts, aircraft parts, nuclear plant material and shipbuilding materials. They are also used to fabricate various domestic items like kitchen utensil and packaging. Due to its high conductivity, pure aluminum is used for electrical transmission lines and protective coating on the surface of other metals. Alloying aluminum with different metals enhances its mechanical properties and makes it suitable for structural applications. However, mechanical alloying of aluminum by casting and other techniques may not be cost-effective, when only the properties at the surface need to be changed.In this thesis, the motivation is implementing the cost-effective method of surface modification of commercially pure aluminum. For this, a continuous wave CO2 laser was used. Laser surface alloying (LSA) was conducted by adding additional metal and ceramic materials to the aluminum substrate and high energy laser beam was used to melt pre-placed material as well as a portion of substrate aluminum. For LSA, powders of copper, magnesium, manganese, titanium and zinc were used. The average particle size of each powder was about 10 μm. In order to investigate the effect of the material combination on the alloy formed, copper, magnesium and manganese were mixed by a ratio of 2:1:1 and alloyed with aluminum substrate.