Alpha alloys contain elements such as aluminum and tin and are preferred for high temperature applications because of their superior creep characteristics. For example, vanadium, niobium, and molybdenum decrease the α-to-β transformation temperature and promote the formation of the β phase. Alloying elements either raise or lower the temperature for the α-to- β transformation, so alloying elements in titanium are classified as either α stabilizers or β stabilizers. When the temperature of pure titanium reaches 885 ☌ (called the β transus temperature of titanium), the crystal structure changes to a bcc structure known as beta (β) phase. At room temperature, unalloyed (commercially pure) titanium has a hexagonal close-packed (hcp) crystal structure referred to as alpha (α) phase. Titanium exists in two crystallographic forms.
They are light in weight, have extraordinary corrosion resistance and the ability to withstand extreme temperatures. Such alloys have very high tensile strength and toughness (even at extreme temperatures). Titanium alloys are metals that contain a mixture of titanium and other chemical elements. This mixture has a solid solubility which varies dramatically with temperature, allowing it to undergo precipitation strengthening. Although “commercially pure” titanium has acceptable mechanical properties and has been used for orthopedic and dental implants, for most applications titanium is alloyed with small amounts of aluminium and vanadium, typically 6% and 4% respectively, by weight.
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