A metallic element, titanium is recognized for its high strength-to-weight ratio. It is a light, strong metal with low density that, when pure, is quite ductile (especially in an oxygen-free environment), lustrous, and metallic-white in color. The relatively high melting point (over 1,649°C or 3,000°F) makes it useful as a refractory metal.
Commercial (99.2% pure) grades of titanium have ultimate tensile strength of about 63,000 psi (434 MPa), equal to that of some steel alloys, but are 45% lighter. Titanium is 60% heavier than aluminium, but more than twice as strong as the most commonly used 6061-T6 aluminium alloy. Certain titanium alloys (e.g., Beta C) achieve tensile strengths of over 200,000 psi (1380 MPa). However, titanium loses strength when heated above 430°C (800°F).
It is fairly hard (although not as hard as some grades of heat-treated steel), non-magnetic and a poor conductor of heat. Machining requires precautions, as the material will soften and gall if sharp tools and proper cooling methods are not used. Like those made from steel, titanium structures have a fatigue limit which guarantees longevity in some applications.
The metal is a dimorphic allotrope with the hexagonal alpha form changing into the body-centered cubic (lattice) beta form at 882°C (1,619°F). The specific heat of the alpha form increases dramatically as it is heated to this transition temperature but then falls and remains fairly constant for the beta form regardless of temperature. Similar to zirconium and hafnium, an additional omega phase exists, which is thermodynamically stable at high pressures, but which may exist metastably at ambient pressures. This phase is usually hexagonal (ideal) or trigonal (distorted) and can be viewed as being due to a soft longitudinal acoustic phonon of the beta phase causing collapse of (111) planes of atoms.
|ASTM B265||Plate and Sheet|
|ASTM B337||Pipe (Annealed, Seamless and Welded)|
|ASTM B338||Welded Tube|
|ASTM B348||Bar and Billet|
|ASTM B862||Pipe (As welded, no anneal)|
|ASTM B863||Wire (Titanium and titanium alloy)|
|ASTM F1108||6Al-4V Castings for surgical implants|
|ASTM F1295||6Al-4V Niobium alloy for surgical implant applications|
|ASTM F1341||Unalloyed titanium wire for surgical implant applications|
|ASTM F136(e-1)||6Al-4V ELI alloy for surgical implant applications.|
Editorial changes were made throughout March 1994
|ASTM F1472||6Al-4V for Surgical implant applications|
|ASTM F620||6Al-4V ELI Forgings for surgical implants|
|ASTM F67||Unalloyed titanium for surgical implant applications|
Examples: Titanium Gr 5 is Ti-6AI-4V
Titanium Gr 2 is known as commercially pure (CP Gr2)