查看更多>>摘要：Local Rapid Heat Treatment (LRHT) based on induction-heating methods can be used to form unique location-specific microstructures and properties in commercial titanium alloys while maintaining the bulk of the material in an initial, non-heat-treated condition. The present work is focused on practical aspects of LRHT application for microstructure/ mechanical properties improvement of some parts made of commercial titanium alloys. It is shown, that LRHT application could improve mechanical properties of such complicated part like turbine engine compressor blades, and two made of Ti-6Al-4V and VT22 titanium alloys goods after repair with Electron Beam Physical Vapor Deposition as well as with Build-up Welding.
查看更多>>摘要：This work investigated the microstructure and elevated-temperature (400-475℃) tensile and tensile-creep deformation behavior of a powder metallurgy (PM) rolled Ti-6Al-4V-1B(wt.%) alloy. The PM rolled Ti-6Al-4V-1B alloy exhibited a duplex microstructure, and it did not exhibit a strong α-phase texture compared with the PM extruded Ti-6Al-4V-1B alloy. The PM rolled Ti-6Al-4V-1B alloy exhibited greater creep resistance than the PM extruded Ti-6Al-4V-1B alloy as well as the as-cast Ti-6Al-4V-1B alloy.
查看更多>>摘要：Laser Beam Welding of ATI 425~? Alloy was performed on 2.5 mm thick butt joints. This new alloy could be used in place of standard Ti-6Al-4V for a variety of lower-cost structural solutions.Demonstration of its fusion weldability with laser welding is of particular interest because it is a near-net- shape process, capable of high welding speeds, which will further enable lower cost manufacturing options. It was found that ATI 425~? Alloy could be successfully welded using a fiber laser at speeds over 3 m/min. Microstructural, microhardness and tensile property evaluations were performed on the resulting welds. It was found that there was a 15% hardness increase in the weld and the strength of the joints was within 2% of base metal properties.
查看更多>>摘要：Heat treatment processes for standard fusion welding techniques in titanium are well established, but the optimal heat treatment for Friction Stir Welded titanium has not been evaluated. In this study, 6 mm thickness titanium 6Al-4V butt welds were subjected to heat treatments ranging from 700 to 900 C. Results of the metallographic analysis for each heat treatment condition will be presented in addition to microhardness, tensile and fatigue properties. It was found that increased heat treatment temperatures lead to lower hardness and tensile strengths, higher elongation to failure and improved high cycle fatigue performance. Furthermore, fracture toughness and crack growth tests were performed for welds subjected to a standard post-weld stress relief. The fracture toughness was lower than the parent material, but crack growth rates in the weld were similar to that of the base metal.
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