Oxygen affinity of titanium melts
The oxygen affinity of titanium melts describes how strongly titanium reacts with oxygen, leading to embrittlement. High affinity results in many pores.
Physicochemical Mechanism of Action
Titanium melt has a strong affinity for oxygen, meaning it strongly absorbs dissolved oxygen. This leads to the incorporation of oxygen atoms as interstitials in the titanium structure, causing embrittlement and porosity.
Metallurgical Relevance & Welding Risks
High oxygen affinity can lead to severe embrittlement of the weld. This increases the risk of hot cracking and reduces the strength of the joint. Additionally, it can cause poor weldability because porosity makes the structure uneven.
Workshop Practice & Action Instructions
To control the oxygen affinity of titanium melts, careful deoxidation is important. This can be achieved by using deoxidizers such as silicon or potassium chloride. The melt should be held at low temperatures and long dwell times to minimize porosity. During cooling, a controlled cooling rate is required to avoid embrittlement.