Materials Engineering Project

This paper has also discussed the different applications of titanium alloys and its limitations in different uses in the modern society. Introduction Titanium alloy is a metal that consists of mixture titanium as the main element and other elements. This is done to achieve high toughness and tensile strength. Generally, alloys have extreme temperature resistance, resistance to corrosion and yet they are light in weight. The process of Titanium Alloying involves the allotropic transformation of pure titanium to the cubic beta phase at very high temperatures of 882.50C (Joshi, 2006). Elements used for alloying normally act as stabilizers at beta or alpha phase. However, by using alloying additions, it is possible to have alpha phase coexisting with beta phase at room temperatures. This is the principle behind manufacture of titanium alloys that can withstand high temperatures during heat strengthening. Titanium alloys are classified into three major groups. beta alloys, alpha alloys and alpha-beta alloys. Alpha is formed by addition of neutral alloying materials as well as alpha stabilizers such as Sn and Aluminum Oxygen respectively. Beta alloys on the other hand contain enough beta stabilizers that enable such alloys to retain their beta phase even after quenching. The strength of beta alloys can also be increased through subjecting them to solution treatment and aging. The third category of titanium alloys is beta-alpha alloys that contains both beta and alpha stabilizers thus withstand heat treatments at various degrees. It is important to note that the nature of alloy and stabilizers used greatly influence the heat stability, toughness, tensile strength and other mechanical properties. Production of Titanium Alloys Kroll Extraction Process Titanium alloy is made from Titanium metal and other chemical elements. The main production process for titanium metal is called Kroll process. It involves treatment of the main ore known as rutile with chlorine gas in order to get a compound known as Titanium tetrachloride. This compound is then purified and reduced by sodium or magnesium to produce metallic titanium sponge. It is the Titanium sponge that undergoes several alloying process that involve heating and melting to produce Titanium Alloys. In this respect, the purity of titanium resulting from Kroll process is therefore critical for alloying process. According to Leyens Peters (2003), the purity of titanium Produced depends on the purity of the starting material as well as the parameters and treatments. His is because there are several metallic elements that may cause very undesirable impacts even when they are present in small amounts. Melting Process The second stage in the production of titanium alloys is the melting process. Melting process involves combination of extracted Titanium alloy with alloying elements depending on the type of alloy to be produced. There are about five melting processes: induction Skull melting, vacuum arc remelting, plasma arc melting, Electroslag refines and Plasma Arc melting Process (Joshi, 2006). Melting process begins by blending together alloying elements with sponge followed by hydraulic pressing necessary to produce excellent blocks known as briquette. Apart from sponge, other titanium from scroll process such as scrap or Revert can also be used depending on the quality of the final Titanium Alloy