Processing and Characterization of Al3Sc precipitates in Cast Aluminum Alloy by Foundry Route
Keywords:
age-hardening, Al3Sc-particles, cast metallurgy, mechanical properties, resistance to recrystallizationAbstract
The aluminum alloy has been prepared through foundry route. It is well known that the ternary Al-Zn-Mg alloy is widely used in aerospace applications due to unique of combination lightweight and high mechanical properties. Its strength and light weight are also desirable in many engineering fields. Therefore, the grain refinement of aluminum alloy is achieved by the addition of inoculant particles (e.g. Al3Sc) in the form of Al-Sc master alloy during in melt practice. As the Al3Sc phase has an ordered L12 crystal structure and a small lattice mismatch with aluminum of only 1.5%, which is coherent with the matrix. The Al3Sc primary particles act as very effective nucleation sites for ?-Al and with the ability of anti-recrystallization, hence the refinement of the as-cast aluminum alloy is carried out. With the addition of 0.1 to 0.7 wt.% scandium (Sc), the castings with refined grain structures were produced. It is desirable in most castings as a fine grain structure generally leading to improved mechanical properties and thermal stability. In addition, there are several characterization has been carried out to cause behind acceleration of ageing kinetics to studied OM, Vicker’s hardness measurement, SEM, FESEM, DSC, and TEM. In the present work, it has to summarize the effect of Al3Sc particles on the kinetics of precipitates and grain refining mechanisms in Al-Zn-Mg alloys during age-hardening phenomena and enhancement on mechanical properties. The paper presents the result of research aimed at studying the effect of Al3Sc precipitates on resistance to recrystallization in aluminum alloys
References
(2) The strength increments cause by additions of Sc have mainly derived from refining strengthening of primary Al3Sc particles formation during solidification of Al-Zn-Mg alloy. (3) Most important strengthening of Sc additions in aged Al-Zn-Mg alloy has Orowan strengthening of secondary Al3Sc particles.
(4) The SEM examination has been proved for Al3Sc particles agglomeration tendency.
(5) The TEM examination revealed fine precipitates and Al3Sc particles.
(6) The DSC is a valuable and efficient technique to analyse a number of reactions that indicate anti-recrystallization effects and dissolution of hardening precipitates.
(7)The ultimate tensile strength of Al-Zn-Mg-Sc alloys increased due to the effect fine dispersion of Al3Sc precipitates, sub-grain and fine-grain strengthening.
References
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