Investigation of Grain Refining in Aluminum Casting Alloys by Thermal Analysis

Grain refinement plays a crucial role in improving the properties of cast and wrought aluminum alloys. Generally, the Al–Ti and Al–Ti–B master alloys are added to Al alloys for their grain refinements. Mechanism of grain refinement is of considerable controversy in the scientific literatures and has been the subject of intensive research. There is a common question for all producers of cast Al alloys of how can be sure about the nucleation quality. Thermal analysis is an important tool to answer this question. In this research, different types of the inoculants were used to investigate nucleation in A356 Al alloy. The cooling curve of each sample was recorded and with the help of a special computer program, the first derivative was calculated. By calculating the zero curve, and analyzing the cooling curve, it was possible to predict the nucleation quality and calculate the solid fractions, latent heats and other information. Results from this research showed that if the maximum under-cooling nucleation was approximately at 3.8 C, quality of the nucleation process becomes more reliable.

کلیدواژه ها:

Thermal Analysis ، Grain Refining ، Nucleation ، A-356 Aluminum