Effect of welding parameters on microstructure characteristics and fatigue properties of dissimilar joints prepared by linear friction welding on TC11 and TC17 titanium alloys

Dissimilar joints between Ti-6Al-4V (Ti-64) and Ti-6Al-2Sn-4Zr-2Mo-0.1Si (Ti-6242) were manufactured using linear friction welding. The weld quality, in terms of the microstructure and mechanical properties, was investigated after stress relief annealing (SRA) at 750 °C for 2 h and compared with the as-welded (AWed) results. The central weld zone (CWZ) microstructure in the AWed condition consisted of recrystallized prior-β grains with α’ martensite, which transformed into an acicular α+β structure after SRA. The hardness in the AWed condition was highest in the CWZ and decreased sharply through the thermomechanically affected zones (TMAZ) to the parent materials (PMs). After SRA, the hardness of the CWZ decreased, mainly due to tempering of the α’ martensite microstructure. Static tensile testing of the dissimilar welds in both the AWed and stress relief annealed (SRAed) conditions resulted in ductile fracture occurring exclusively in the Ti-6Al-4V side of the joint. The promising results on joining of Ti-64 to Ti-6242 provide valuable insight for tailoring performance of next-generation aero-engine products.

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Dissimilar linear friction welding between a SiC particle reinforced aluminum composite and a monolithic aluminum alloy: Microstructural, tensile and fatigue properties

Materials Science and Engineering A ◽

10.1016/j.msea.2012.09.033 ◽

2013 ◽

Vol 559 ◽

pp. 852-860 ◽

Cited By ~ 23

Author(s):

F. Rotundo ◽

A. Marconi ◽

A. Morri ◽

A. Ceschini

Keyword(s):

Aluminum Alloy ◽

Friction Welding ◽

Fatigue Properties ◽

Linear Friction Welding ◽

Aluminum Composite ◽

Linear Friction ◽

Sic Particle

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MODELING OF TITANIUM ALLOYS PLASTIC FLOW IN LINEAR FRICTION WELDING

Facta Universitatis Series Mechanical Engineering ◽

10.22190/fume201225014s ◽

2021 ◽

Vol 19 (1) ◽

pp. 091

Author(s):

Vladimir A. Skripnyak ◽

Kristina Iokhim ◽

Evgeniya Skripnyak ◽

Vladimir V. Skripnyak

Keyword(s):

Plastic Deformation ◽

Titanium Alloys ◽

Plastic Flow ◽

Friction Welding ◽

Welded Joint ◽

High Tech ◽

Structural Elements ◽

Linear Friction Welding ◽

Near Surface ◽

Linear Friction

The article presents the results of the analysis of the plastic flow of titanium alloys in the process of the Linear Friction Welding (LFW). LFW is a high-tech process for joining critical structural elements of aerospace engineering from light and high-temperature alloys. Experimental studies of LFW modes of such alloys are expensive and technically difficult. Numerical simulation was carried out for understanding the physics of the LFW process and the formation laws of a strong welded joint of titanium alloys. Simulation by the SPH method was performed using the LS DYNA software package (ANSYS WB 15.2) and the developed module for the constitutive equation. The new coupled thermomechanical 3D model of LFW process for joining structural elements from alpha and alpha + beta titanium alloys was proposed. It was shown that the formation of a welded joint occurs in a complex and unsteady stress-strain state. In the near-surface layers of the bodies being welded, titanium alloys can be deformed in the mode of severe plastic deformation. A deviation of the symmetry plane of the plastic deformation zone from the initial position of the contact plane of the bodies being welded occurs during a process of LFW. Extrusion of material from the welded joint zone in the transverse direction with respect to the movement of bodies is caused by a pressure gradient and a decrease in the alloy flow stress due to heating. The hcp-bcc phase transition of titanium alloys upon heating in the LFW process necessitates an increase in the cyclic loading time to obtain a welded joint.

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