Papers by Keyword: Al-Si-Fe Based Alloy

Abstract: Two atomized alloy powders, those chemical compositions are Al-10Si-5Fe-1Zr and Al- 10Si-5Fe-4Cu-2Mg-1Zr, were pre-compacted by cold pressing with 350MPa and subsequently hot forged at temperatures ranging from 653K to 845K and at an initial strain rate of 10-2/s in order to produce bulk cylindrical type alloys with the diameter of 10 mm. The addition of Cu and Mg into the present alloy causes a decrease in the eutectic reaction temperature of Al-10Si-5Fe-1Zr alloy from 841K to 786K and results in a decrease of flow stress at the given forging temperature. TEM observation revealed that in addition to Al-Fe based intermetallics, Al2Cu and Al2CuMg intermetallics appeared to display the alloying effect additionally. The volume fraction of intermetallic dispersiods increased by the addition of Cu and Mg. Compressive strength of the present alloys was closely related to the volume fraction of intermetallic dispersoids.

Abstract: The mechanical properties of pre-sintered Al-10Si-5Fe-1Cu-0.5Mg-1Zr (wt%) alloy were investigated in the temperature range from 673K to 813K and at initial strain rates from 10-4 to 100 s-1. In the high temperature range of 793K and 813K, the strain rate sensitivity index was close to that for superplasticity (0.3). Stress exponent was estimated to be 2 and 5 in the temperature range from 793K to 813K and from 673K to 773K, respectively. The activation energies for the plastic flow were calculated to 77kJ/mol for the n=2 region and 127kJ/mol for the n=5 region. These values were close to that for grain boundary diffusion and self-diffusion in pure aluminum, respectively. We found that a dynamic recrystallization (DRX) and grain boundary sliding (GBS) occur depending on the test temperature and stain rate. A filament-like phase containing Cu and Mg was observed in the cracked surface of the specimen deformed at 793K and 813K.

Abstract: Compressive deformation behavior of pre-sintered Al-10Si-5Fe-1Cu-0.5Mg-1Zr (wt%) alloy containing 15% of porosity was investigated in the temperature range from 753 K to 793 K and at strain rates from 10-4 to 100 s-1. From the microstructural observation, it was revealed that the occurrence of grain boundary sliding accomodated by dynamic recrystallization during the compressive deformation was closely associated with the considerable decrease in the porosity of the pre-sintered alloy. In the specimens deformed at 793 K with 10-4~100 s-1 and at 773 K with 10- 4~10-2 s-1, we have found an evidence of the occurrence of a liquid phase during compressive deformation in the microstructure. The liquid phase was considered to promote particle boundary sliding and hinder the reduction of the pore.