Materials for engineering, 3rd Edition - (Malestrom)

90
Materials for engineering
Weight %
60 70 80 90 100
L
649°C
L + α
α + β
437°C
(Mg)
80 100
Atomic %
Mg
3.10 The Mg-rich end of the Mg–Al phase diagram.
Wrought magnesium alloys
The most widely-used sheet alloy is Mg–3Al–1Zn–0.3Mn, which is
strengthened by strain hardening. A range of extrusion alloys exist, based on
Mg–Al–Zn, with Al contents between 1 and 8%, but the highest room
temperature strength is found in the Mg–6Zn–0.7Zr alloy when it is aged
after extrusion. The mechanical properties of some magnesium alloys are
given in Table 3.4.
3.2.3 Titanium alloys
Aerospace applications account for some 80% of titanium that is produced,
most of the remainder being used in the chemical industry since its protective
oxide film gives it relative chemical inertness. Titanium alloys show an
outstanding resistance to corrosion by body fluids, superior to that of stainless
steels, and this has led to their use in prosthetic devices. Titanium has a low
density and high melting point (1678°C) making titanium alloys suitable for
certain critical gas turbine components.