A Review on Inertia and Linear Friction Welding of Ni-Based Superalloys
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NI-BASED superalloys play an essential role in aerospace and power generation industries. Application of these alloys for various components in gas turbine engines has provided higher operation temperatures and improved efficiency. Such applications are due to their high temperature strength, fatigue, and creep resistance as well as satisfactory resistance to corrosion and oxidation under harsh service conditions.[1,2] These alloys are mainly precipitation-strengthened, either by c¢, Ni3(Al, Ti) or by a combination of c¢¢, Ni3Nb, and c¢.[2,3] Also, alloying elements such as Co, Fe, Cr, Ti, Al, Nb, Mo, W, and Ta supply extra strength by solid solution mechanisms.[4] Moreover, carbides precipitate at grain boundaries and improve creep resistance through inhibiting or retarding grain boundary sliding
AHMAD CHAMANFAR, Postdoctoral Fellow, and MOHAMMAD JAHAZI, Professor, are with the De´partement de Ge´nie Me´canique, E´cole de Technologie Supe´rieure, 1100 rue Notre-Dame Ouest, Montreal, QC H3C 1K3, Canada. Contact e-mail: [email protected] JONATHAN CORMIER, Professor, is with the Institut Pprime, CNRSENSMA-Universite´ de Poitiers, UPR CNRS 3346, De´partement de Physique et Me´canique des Mate´riaux, ENSMA- Te´le´port 2, 1 avenue Cle´ment Ader, BP 40109, 86961 Futuroscope-Chasseneuil, Cedex, France. Manuscript submitted June 4, 2014. Article published online 7 February 2015 METALLURGICAL AND MATERIALS TRANSACTIONS A
at high temperatures.[5] The corrosion resistance is mainly provided by Cr and Al through formation of protective Cr2O3 and Al2O3 oxide films.[6] Effective industrial application of Ni-based superalloys necessitates the use of welding in manufacturing of engine components with complex geometries and repair of parts damaged during service.[7,8] Generally, the manufacturing and repair processes are carried out using fusion welding techniques such as gas-tungsten-arc welding, electron beam welding, or laser welding.[9] While fusion welding of solid solution strengthened Nibased superalloys are commonly carried out, the welding of high strength, precipitation hardened Ni-based superalloys has been a challenging issue over the years, because these alloys are prone to solidification cracking, heat affected zone (HAZ) cracking, strain age cracking, segregation of alloying elements, and formation of porosity in the weld zone.[10–13] These problems limit the manufacturing and repair weldability of Ni-based superalloys.[13] To address this issue, solid state joining techniques such as inertia friction welding (IFW) and linear friction welding (LFW) have been considered as alternative joining techniques. In these techniques, since joining occurs in the solid state, bulk melting of the weld parts does not take place.[14] Therefore, weld defects associated with melting and resolidification such as solidification cracking, solute segregation, and porosity formation are avoided.[11,15,16]
VOLUME 46A, APRIL 2015—1639
Fir-Tree Blade Disk
Fig. 1—Mechanical fastening of blades in disk using a fir-tree arrangement in g
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