Titanium is a metallic element, gray, with atomic number 22 and relative atomic mass 47.867. Can burn in nitrogen, high melting point. Passive titanium and titanium-based alloys are new structural materials, mainly used in the aerospace industry and the marine industry.

Because titanium has the characteristics of high melting point, small specific gravity, high specific strength, good toughness, fatigue resistance, acid and alkali corrosion resistance, low thermal conductivity, good high and low temperature tolerance, and low stress under rapid cooling and rapid heating conditions, its commercial value is in Since the 1950s, it has been recognized by people and has been used in high-tech fields such as aviation and aerospace.

1. Physical properties Pure titanium is silver-white. Compared with other metal materials, the characteristics of titanium are as follows:

1) The melting point is as high as 1660 degrees.

2) Titanium exhibits a hexagonal close-packed lattice at room temperature (below 885 degrees) and a body-centered cubic lattice above 885 degrees, with a 5.5% increase in volume.

3) The density of titanium is about 4.51g/cm3, which is about 60% of that of stainless steel, more than that of aluminum, and about 60% larger than that of aluminum.

4) Although the tensile strength of pure titanium is 350-700MPa, the general titanium alloy can reach 700-1200MPa, or even 1400MPa. Therefore, the specific strength of titanium alloys (that is, the ratio of strength to density) is greater than that of any other material at present.

5) The specific heat, thermal conductivity and resistivity of titanium are at the same level as those of stainless steel, but the expansion coefficient of titanium is 50% smaller than that of steel. Titanium has poor thermal conductivity and poor electrical conductivity, similar to stainless steel.

6) The Young's modulus of titanium is smaller than that of stainless steel, and it can bend under lower stress.

7) Follow stable creep characteristics in the temperature range of 200-300 °C.

2. Chemical properties

1) At room temperature, titanium is not easy to react with inorganic acid, but it can react after heating.

2) Action with alkali Titanium reacts very slowly with ordinary alkali solutions and does not react with dilute alkali solutions.

3) Interaction with non-metals In general, titanium is not very active, but at high temperatures, titanium can directly form very stable, hard and insoluble interstitial compounds with many non-metallic elements.

4) An important property of titanium is its ability to strongly absorb gases (oxygen, nitrogen, hydrogen). The role of titanium and oxygen and nitrogen is irreversible, so titanium is a good getter. The hydrogen absorbed in titanium can be discharged from the metal when it is heated to 800-900 degrees in a vacuum.