Materials for engineering, 3rd Edition - (Malestrom)

Metals and alloys 101
700
600
500
660
At% Zn
10 20 30 40 50 60 70 80 90 100
Liquid
Temperature (°C)
400
300
200
α 419
382
351.5
α′ 82.8 95
275
98.86
β
31.6
78
99.3
100
4.0
0
0 10 20 30 40 50 60 70 80 90 100
Wt% Zn
3.19 The Al–Zn phase diagram.
with zinc-rich dendrites, whereas the hypereutectic contain Al-rich dendrites.
The commercial alloys contain strengthening additions of copper and
magnesium, but the greatest care has to be taken to prevent excessive pickup
of harmful impurity elements such as lead, cadmium, tin and iron. The
alloys themselves are prepared from high-purity components, otherwise
intergranular embrittlement of the castings develops over a period of time.
The properties of some lead, zinc and nickel alloys are presented in
Table 3.7.
3.2.7 Nickel alloys
Commercially pure nickel offers excellent corrosion resistance to reducing
environments (in contrast to those metals and alloys which owe their resistance
Table 3.7 Typical mechanical properties of some lead, nickel and zinc alloys
Alloy Condition Density Young’s Yield UTS Elongation
Mg m –3 modulus stress MPa (% in
GPa MPa 50 mm)
Lead >99.99% 11.68 16.1 – 168 –
Zn–8.5Al–1Cu (ZA8) Die cast 6.3 86 290 375 6–10
Ni–30Cu–1.5Fe–1Mn Hot rolled 8.83 180 230 560 45
Ni–20Cr–2Ti–1.5Al Fully aged 8.19 222 780 1220 30
Nimonic 80A