Volume 18, Issue 2 (March 1990)
Effect of Crystallographic Texture on Flexure Fatigue Properties of Ti-3Al-2.5V Hydraulic Tubing
Ti-3Al-2.5V alloy has long been known to have strong anisotropic mechanical properties due to its hexagonal crystal structure. Early workers discovered that tubing made from this alloy had enhanced fatigue resistance when crystals were oriented in a “radial” direction as opposed to the “tangential” direction. The focus of this current work was to test the impact of texture on flexure fatigue strength over a wide texture range and find if an optimum crystallographic texture existed for fatigue resistance. The results show that an optimum crystal orientation does indeed exist and that tubing with a texture either less radial or more radial displays lessened fatigue life.
The lessened fatigue life of highly radial tubing was previously unknown and is not well understood. The findings from this work should be considered by engineers when designing aerospace hydraulic systems and a texture range, not just a minimum, should be specified.