Influência da adição de três composições dos refinadores de Ti-B na microestrutura da liga de alumínio A380

Abstract

Aluminum is the most important non-ferrous metal and the second most used metal in the world and the knowledge of its metallographic characteristics is really important for its correct use, as well as the influence that the addition of grain refiners can bring to such characteristics. The incorporation of Ti and B in aluminum alloys can bring the property of refining grains and changing hardness. The analysis of the influence of these materials on the hardness and grain refining, in the A380 alloy, added to the two pouring temperatures of 650ºC and 680ºC, is presented in an important way for its correct application. For this analysis, the aluminum alloy was melted in four compositions, being aluminum without refiners and with refiners 3Ti1B, 5Ti1B and 5Ti2B, using the two casting temperatures mentioned above. After metallographic analysis by optical microscopy and scanning optical microscopy, it was possible to notice that there was a decrease in the grain size when the refiners were added. In the Rockwell K hardness analysis, chosen for having a larger indent, it was noted that the hardness increases with the addition of refiners more noticeably at a temperature of 650ºC, when compared with the increase in hardness at a temperature of 680ºC.