Utilization of Die Casting with Varying Mold Wall Thicknesses to Produce 6082 Aluminum Alloy treated with Al5Ti1B Grain Refiner and Assess its Mechanical Properties

One of the most popular wrought alloys with significant industrial interest is aluminum 6082 alloy. This study used a permanent mold casting process to fabricate aluminum 6082 alloy with varying percentages of grain refiner Al5Ti1B master alloy and varying mold wall thicknesses (7.5, 17.5, and 27.5 mm). The investigation focused on the impact of adding different weight percentages of Al5Ti1B on the microstructure and mechanical characteristics of 6082 aluminum alloy. Using Vickers hardness testing machine with a load of 100 g, the bulk hardness was estimated. The investigated alloys microstructure characteristics were obtained through the use of optical microscopes, SEMs, EDS, and X-ray diffraction. Based on the available data, the 6082 aluminum alloy exhibited improved mechanical properties and a finer-grained structure after the addition of Al5Ti1B grain refiner (from 0 to 2 weight percent). By adding grain refiner alloy from 0 to 2%, the grain size of the 6082 aluminum alloy was reduced from 81 to 45µm. The microstructure alterations resulted in a notable enhancement of the 6082 aluminum alloys mechanical characteristics. The yield strength increased from 127 to 162 MPa, and the UTS improved from 166 to 225 MPa with the increase of Al5Ti1B grain refiner from 0 to 1.5% weight percentage. Additionally, the value of elongation increased from 6.7 to 16.6%. As the amount of Al5Ti1B grain refiner increased, the hardness of the aluminum alloy 6082 also increased. During solidification, as the mold wall thickness increased, the rate of cooling increases, and as a result, the as-cast dendritic grains reduced. The inner surface of the casting displays coarse grains, whereas the microstructure of the casting close to the mold wall displays fine-grain structure. As the current study indicates, this will lead to a higher microhardness in the vicinity of the mold wall and a lower microhardness at the inner of the casting.