The effects of degassing, grain refinement \& Sr-addition on melt quality-hot tear sensitivity relationships in cast A380 aluminum alloy
Uludag, Muhammet and Cetin, Remzi and Dispinar, Derya and Tiryakioglu,
Murat
Loading
Abstract
Hot tearing tendency of A380 with various element additions (Sr, Sr +
Ti, Ti, B and B + Sr) was investigated. Constrained rod casting (CRC)
hot tearing test method was used to characterize the hot tearing
sensitivity. Reduced pressure test (RPT) samples were produced from each
condition and all trials were repeated three times. Number density of
pores on the cross section of RPT samples was calculated via digital
image processing and statistical analysis was carried out.
Microstructure analysis was carried out to observe the effect of
alloying elements. Hot torn cross sections were subjected to SEM
analysis. It was found that in aluminum alloys, the most deleterious
defects, bifilms that are the cause of many defects, play an important
role in initiating the hot tearing during solidification. It is
important to note that the shape, size and distribution of bifilms are
too complex. They act as heterogeneous nucleation site for liquid to
separate and thus increase hot tearing.... Show more Show less