MICROSTRUCTURES AND MECHANICAL PROPERTIES OF RAPIDLY SOLIDIFIED Al-Fe-Cr-Zr-V-Si ALLOY AND THEIR THERMAL STABILITY
(Department of Materials Science and Engineering, Central South University of Technology, Changsha 410083, P. R. China)
Abstract: The rapidly solidified powder of Al-Fe-Cr-Zr-V-Si alloy was prepared using multi-stage atomization rapid solidification device and then consolidated by hot extrusion after cold isostatic pressing and vacuum degassing. The microstructures, room-and elevated-temperature mechanical properties of the consolidated material and their thermal stability were studied by optical microscopy, transmission electron microscopy, hardness test and tensile test. The results show that this alloy has excellent mechanical properties at room and high temperatures and good thermal stability, and it exhibits good heat-resistance at least below 400℃. The main second phases that strengthen this alloy are Al12(Fe,Cr,V)3Si and Al3Zr, of which the Al12(Fe,Cr,V)3Si silicide is of bcc structure (a=12.6 ) and has excellent thermal stability and coarsening resistance.
Key words: rapid solidification powder metallurgy heat-resistant aluminium alloy Al-Fe-Cr-Zr-V-Si