Authors: S Nouri S Rastegari Sh Mirdamadi M Hadavi
Publish Date: 2015/03/29
Volume: 68, Issue: 5, Pages: 867-871
Abstract
In this investigation Ti–48Al–2Nb–2Cr at alloy was aluminized by two kinds of pack cementation processes inpack and outpack processes In both methods pack powder mixture consisting of 10 wt Al 5 wt AlCl3 and balance Al2O3 was used to aluminize γTiAl at 1000 °C for 6 h The coated samples were characterized by XRD and SEM The results indicated that a singlelayered TiAl3 coating by thickness of approximately 100 μm was formed by the use of inpack method but a twolayered aluminide coating including an outer thin layer of TiAl3 with thickness of approximately 2 μm and also an inner layer of TiAl2 with thickness of approximately 10 μm was formed by outpack process In both methods aluminide coatings with uniform structure free from any microcracks were formed on the surface of the substrates The results showed that the flux of active aluminum atoms on the substrate surface in outpack method is to be expected to be much slower than inpack method
Keywords: