Fabrication of Rapidly Solidified Al-20wt%Si-5wt%Fe Alloy Powder and Mechanical Properties of its Extrudates

급속응고 Al-20wt%Si-5wt%Fe 합금분말 압출재의 강도에 관한 연구

Optical microstructures and mechanical properties of Na gas atomized Al-20Si-5Fe alloying powder and its hot extrudates were studied on 3 different types of powder size distribution. This powder showed the size distribution of 10~210 $\mu\textrm{m}$. Also the microstructures of $\alpha$-Al, primary and eutectic Si and needle shaped intermetallic compounds were observed by optical microscope. These needle shaped intermetallic compounds were identified as ${\delta}Al_4FeSi_2$- by XRD and EDX analysis. The ultimate tensile strength(UTS) of these alloy extrudates was increased from 324 to 390 MPa with decreasing powder size range from 120~210 $\mu\textrm{m}$ to 10~64 $\mu\textrm{m}$. A value of Micro-vic-kers hardness was simillar to the result of UTS. These extrudates showed better wear resistance than those of Al-20Si-2X(X : Ni, Cr, Zr), although they are insensitive to the size distribution. These results indicate that the presentation of ${\delta}Al_4FeSi_2$ intermetallic compounds contributed to the wear resistance improvement.