1. Physical properties
Among the metal elements, titanium has a high specific strength. It is a high-strength but low-quality metal with fairly good ductility (especially in an oxygen-free environment). The surface of titanium has a silver-white metallic luster. Its melting point is quite high (over 1,649 degrees Celsius), so it is a good refractory metal material. It is paramagnetic, and its electrical and thermal conductivity are very low.
Commercial grade titanium (purity of 99.2%) has an ultimate tensile strength of about 434 megapascals, which is similar to low grade steel alloys, but is 45% lighter than steel alloys. The density of titanium is 60% higher than that of aluminum, but its strength is twice that of the common 6061-T6 aluminum alloy.
Titanium can be used for various purposes. Some titanium alloys (such as βC) have a tensile strength of 1,400 megapascals. However, when titanium is heated to above 430 degrees Celsius, its strength decreases.
Although not comparable to high-grade heat-treated steel, titanium still has considerable hardness. Titanium is not magnetic, and it is also a poor thermal and electrical conductor. Pay attention to mechanical processing, because if sharp tools and proper cooling methods are not used, titanium will soften and leave indentations. Like the steel structure, the titanium structure has a fatigue limit, so it can be guaranteed to be durable in some applications.
The specific stiffness of titanium alloy is generally not as good as other materials such as aluminum alloy and carbon fiber, so it is less used in structures that require high stiffness.
2. Chemical properties
Among the characteristics of titanium, the more praised is its excellent corrosion resistance-its corrosion resistance is almost as good as platinum. Titanium is not corroded by dilute sulfuric acid, dilute hydrochloric acid, chlorine gas, chlorine solution and most organic acids. But it can still be dissolved by concentrated acid. Although the following potential-pH diagram indicates that titanium is a highly active metal thermodynamically, its reaction with water and air is very slow.
