Part. 3: Properties

Titanium presents two crystalline forms with a reversible change at 880°C. The shape α is tetragonal where d = 4,505 g/cm3 at a temperature of 25°C. The β shape is body-centred cubic and presents d = 4,35 g/cm3 at a temperature of 25°C; it melds at 1668°C.

implantologia-elettrosaldata-titanio-protesi-dentale-estetica-fissazione-dentiere
Fig. 2b

The Titanium mechanical characteristics are the following ones: breaking load 560 N/mm2 ; elastic limit 46 kg/mm2; lengthening 25%; hardness 200-220 Brinell.

The Elasticity module is approx. twice the stainless steels 18-8, to which it can be compared being rustproof.

The oxygen solubility is important: for the oxygen around the 4% in weight in the β shape and up to 33% in the α shape.

The Titanium passivates naturally at environmental temperature or in contact with fluids of the tissues. In accordance with the Osseo-integrative Theory, Titanium oxide creates a tight chemical link with the metal, thanks to the electrostatic chemical forces.

The most common elements used in the titanium-based alloys behave as stabilizers of α-phase or β-phase. The most common for the α-phase is aluminium; otherwise the vanadium lowers the changing temperature β α.

Titanium commercially pure is classified in 5 degrees (1, 2, 3, 4, 7) by ASTM norm. The following diagram compares the characteristics of the main construction metals.

Titanium Iron Steel Aluminium Copper
Specific weight

4,5

7,3

7,9

2,7

8,9
(g/cm^3)
Melting point

1668

1530

1400-1420

660

1083
(°C)
thermal

0,041

0,15

0,039

0,49

0,92
conductivity
(Cal/cm^2/S/°C/cm)
Young module

10850

21000

20400

6900

1100
(N/mm^2)

Tab.1