198
M. S. Dani and I. B. Dave
Fig. 1 Schematics of friction stir processing (FSP) [14]
FSP may be a comparatively new microstructural modification process utilized for
metals and alloys [7–9]. In FSP/FSW [10–13], a rotating tool was inserted into a specimen, and fine grain structure is obtained due to high plastic deformation as shown
in Fig. 1 [14]. Thus, FSP has been accustomed to prepare aluminum and magnesium
alloys with fine and ultrafine grains. In FSPed metal alloys, the grain size may be
small to some micrometers, and therefore, the mechanical properties were considerably improved [14–16]. A lot of investigations were done on FSP with intermetallic
particles like SiC particles, Al 2 O 3 particles, SiO 2 particles, C 60 molecules, etc., on
regular cast aluminum or magnesium alloy components. It was often found that the
grain refinement by FSP has targeted on some regular aluminum and magnesium
alloy castings [11], and very few researches have involved pure aluminum powder
on Mg alloys. In Mg alloys, much attention has been paid to enhance the mechanical properties of AZ31 Mg alloy by FSP, whereas, owing to difficulties in FSP of
AZ91 Mg alloy as well as lack of availability of AZ91 Mg alloys sheet form, AZ91
Mg alloy composite producing by FSP was restricted. Therefore, researchers have
used completely different casting strategies for producing of AZ91/ceramic particles composite [12, 17–21]. In this study, FSP was done on commercially available
die-cast AZ91 Mg alloy with and without pure aluminum powder with different
process parameters like rotational speeds, single pass and double pass with same
transverse speed. Micron-size aluminum particles were distributed into AZ91 Mg
alloy to reveal the effect of FSP on microstructure, grain size and microhardness of
different fabricated AZ91 Mg alloy surface layers.
2 Experimental Work
Friction stir processing was done on die-cast AZ91 Mg alloy for surface modification.
The material used in this work was AZ91 die-cast Mg alloy which has the composition
of (in wt%): Al, 9.65; Zn, 0.772; Mn, 0.027; Fe, 0.0098; balance Mg. FSP was done
on the universal milling machine.
M. S. Dani and I. B. Dave
Fig. 1 Schematics of friction stir processing (FSP) [14]
FSP may be a comparatively new microstructural modification process utilized for
metals and alloys [7–9]. In FSP/FSW [10–13], a rotating tool was inserted into a specimen, and fine grain structure is obtained due to high plastic deformation as shown
in Fig. 1 [14]. Thus, FSP has been accustomed to prepare aluminum and magnesium
alloys with fine and ultrafine grains. In FSPed metal alloys, the grain size may be
small to some micrometers, and therefore, the mechanical properties were considerably improved [14–16]. A lot of investigations were done on FSP with intermetallic
particles like SiC particles, Al 2 O 3 particles, SiO 2 particles, C 60 molecules, etc., on
regular cast aluminum or magnesium alloy components. It was often found that the
grain refinement by FSP has targeted on some regular aluminum and magnesium
alloy castings [11], and very few researches have involved pure aluminum powder
on Mg alloys. In Mg alloys, much attention has been paid to enhance the mechanical properties of AZ31 Mg alloy by FSP, whereas, owing to difficulties in FSP of
AZ91 Mg alloy as well as lack of availability of AZ91 Mg alloys sheet form, AZ91
Mg alloy composite producing by FSP was restricted. Therefore, researchers have
used completely different casting strategies for producing of AZ91/ceramic particles composite [12, 17–21]. In this study, FSP was done on commercially available
die-cast AZ91 Mg alloy with and without pure aluminum powder with different
process parameters like rotational speeds, single pass and double pass with same
transverse speed. Micron-size aluminum particles were distributed into AZ91 Mg
alloy to reveal the effect of FSP on microstructure, grain size and microhardness of
different fabricated AZ91 Mg alloy surface layers.
2 Experimental Work
Friction stir processing was done on die-cast AZ91 Mg alloy for surface modification.
The material used in this work was AZ91 die-cast Mg alloy which has the composition
of (in wt%): Al, 9.65; Zn, 0.772; Mn, 0.027; Fe, 0.0098; balance Mg. FSP was done
on the universal milling machine.