Grain Refinement and Improvement in Microhardness of AZ91 Mg …
207
Table 3 Comparison of grain size of FSPed AZ91 without aluminum powder SP and DP with 380
and 545 rpm with untreated die-cast AZ91 Mg alloy
SR No. Specimen
condition
ASTM grain
Size No. (G)
No of
grains/unit
area
(No./in 2 ) at
100×
L Mean
intercept
(μm)
d Avg. dia.
(μm)
A Avg. grain
area (μm 2 )
1
Die-cast
AZ91 Mg
alloy
6.5–7.0
45.25
33.6
37.8
1426
2
AZ91 FSP
380 SP
without Al
9.0–9.5
256
14.1
15.9
252
3
AZ91 FSP
545 SP
without Al
8.5–9.0
181.02
16.8
18.9
365
4
AZ91 FSP
380 DP
without Al
10.5–11.0
724.08
8.4
9.4
89.1
5
AZ91 FSP
545 DP
without Al
11.0–12.0
1024
7.1
7.9
63
Table 4 Comparison of grain size of FSPed AZ91 with aluminum powder SP and DP with 380
and 545 rpm with die-cast AZ91 Mg alloy
SR No. Specimen
condition
ASTM grain
size No. G
No of
grains/unit
area
(No./in 2 ) at
100×
L Mean
intercept
(μm)
d avg. dia.
(μm)
A avg. grain
area (μm 2 )
1
Die-cast
AZ91 Mg
alloy
6.5–7.0
45.25
33.6
37.8
1426
2
AZ91 FSP
380 SP with
Al
9.5–10.5
362.04
11.9
13.3
178
3
AZ91 FSP
545 SP with
Al
9.5–10.5
362.04
11.9
13.3
178
4
AZ91 FSP
380 DP with
Al
11.0–12.0
1024
7.1
7.9
63
5
AZ91 FSP
545 DP with
Al
12.0–13.0
2048
5.0
5.6
31.5