Abstract
Titanium alloys, which are important in aerospace application, offer different properties via changing alloys. As design complexity and service demands increase, dissimilar welding of the titanium alloys becomes a particular interest. Linear friction welding (LFW) is a relatively novel bond technique and has been successfully applied for joining titanium alloys. In this paper, dissimilar joints with Ti-6Al-4V and Ti-5Al-2Sn-2Zr-4Mo-4Cr alloys were produced by LFW process. Microstructure was studied via optical microscopy and scanning electron microscopy (SEM), while the chemical composition across the welded samples was identified by energy dispersive X-ray spectroscopy. Mechanical tests were performed on welded samples to study the joint mechanical properties and fracture characteristics. SEM was carried out on the fracture surface to reveal their fracture modes. A significant microstructural change with fine re-crystallization grains in the weld zone (WZ) and small recrystallized grains in the thermo-mechanically affected zone on the Ti-6Al-4V side was discovered in the dissimilar joint. A characteristic asymmetrical microhardness profile with a maximum in the WZ was observed. Tensile properties of the dissimilar joint were comparable to the base metals, but the impact toughness exhibited a lower value.
Highlights
Dissimilar weld is attracting increasing attention because it can take advantage of specific attributes of each material to enhance the performance of a product or introduce new functionalities.They are applied in various fields such as thermal power station, nuclear industries, automobile, aerospace, etc
There have been a number of studies reporting the welding of dissimilar titanium alloys using various different welding processes, including friction stir welding [3], ultrasonic spot welding [4], linear friction welding (LFW) [5,6], tungsten inert gas welding [7] and electron beam welding [8]
The weld interface appearing wavy is obvious between two base metals
Summary
Dissimilar weld is attracting increasing attention because it can take advantage of specific attributes of each material to enhance the performance of a product or introduce new functionalities. They found different microstructure zones such as the TMAZs and weld zones in both sides of base metals They investigated the mechanical properties and found the tensile strength of the joint was comparable to that of the parent [20]. To predicting various weld responses, such as thermal fields and microstructural evolution, a great number of finite element models were established and the predictions of the models were found to be in good agreement with the experimental results [28,29,30,31] These investigations on LFW joints with dissimilar and similar materials show that the microstructure and property can be established for given LFW joints through extensive experiments. The present study was focused on revealing the micro-structural characterization, mechanical properties, as well as the fracture mode of the dissimilar joints
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
