The origin and overcoming of beta brittleness in titanium alloy forging
Titanium alloy has become an indispensable material due to its excellent properties. However, due to the complexity of its forging process, some defects may occur. Below we have compiled the root causes of beta brittleness and how to overcome it.
The origins of beta brittleness
Beta brittleness is mainly due to the excessive growth of the beta phase (a crystal structure in titanium alloys) when the temperature exceeds its beta transformation temperature during the forging process of titanium alloys. This overgrowth can cause a significant reduction in the plasticity of the titanium alloy, causing it to become brittle. For example, Ti-6Al-4V, a commonly used titanium alloy, is particularly prone to beta brittleness when it is forged at temperatures above 850°C.
Ways to overcome beta brittleness:
Precise control of furnace temperature and forging parameters: This is the most basic and important point. By accurately controlling the temperature in the furnace and various parameters during the forging process, such as pressure, speed, etc., it is possible to ensure that the titanium alloy does not exceed its beta transformation temperature during the forging process, thereby avoiding excessive growth of the beta phase.
Advanced heat treatment technology: After forging is completed, heat treatment of titanium alloy is also an effective method. By adjusting parameters such as heat treatment temperature, time, and cooling rate, the microstructure of titanium alloys can be changed and beta brittleness can be eliminated or reduced.
Reasonable heating and cooling strategy: The rate of titanium alloy during the heating and cooling process is also an important factor affecting its performance. Through reasonable heating and cooling strategies, it is possible to ensure that titanium alloys form an ideal microstructure during the forging process, thereby avoiding the occurrence of beta brittleness.
Use of new alloy elements: In recent years, researchers have discovered that by adding some new alloy elements, such as rare earth elements, the thermal stability of titanium alloys can be significantly improved, thus enhancing its ability to resist beta brittleness.
In summary, although beta brittleness is an important problem in the titanium alloy forging process, through reasonable process control and technical means, we can still effectively overcome it and ensure the performance and application of titanium alloys.
