Friction stir welding/processing of metals and alloys: A comprehensive review on microstructural evolution

Friction-stir welding and processing of Ti-6Al-4V titanium alloy: A review

In this chapter the basic working principles and applicability of the friction stir welding (FSW) process in aerospace and automobile industries are discussed. FSW results in the formation of three microstructural zones, namely weld nugget, thermomechanical-affected zone, and heat-affected zone. An overview of these zones has been provided. Process variables such as tool geometry, joint configurations, and the effect of process parameters have also been discussed in this chapter.

Friction Stir Welding

The application of fusion welding process is restricted to certain grades of alloys and materials. Solid-state joining process offers greater advantages over fusion welding process such as fumeless and effective joining, minimum or no preparation time, environment friendly, etc. One such solid-state joining process is friction stir welding (FSW), which uses a non-consumable rotating tool. This rotating tool joins the two faying surfaces of the workpiece by forging them. This joining technique successfully joins metals, alloys and metal matrix composite (MMC), which are considered as difficult to join using conventional processes. The present study is an endeavor to review a specific domain of FSW, i.e. joining of MMCs. The initial part of the study provides a detailed introduction about the FSW process, and along with it, an overview of the published literature related to FSW of alloys has been presented. The later part of the study pays specific attention to macrostructure, microstructure, joint ...

Joining of metal matrix composites using friction stir welding: a review

Friction stir welding (FSW) offers an appealing solid state joining alternative to traditional fusion welding techniques for titanium alloys because it reduces problems associated with high temperature processing. Propellant tanks are a critical component of every spacecraft and contain several weld seams and a prime candidate for this innovative technology. This paper reviews the current technological maturity of FSW relative to titanium alloys and considers the application with respect to a pressure vessel. FSW is currently in a period of significant investment by large engineering companies and international research institutions. The technology is advancing and evolving to cater for high temperature alloys. Stationary shoulder FSW and hybrid techniques show promising potential with respect to Ti–6Al–4V. The tool material and limited process window for this material are restrictive factors at present but can be overcome with future development.

/pdf/alternative-friction-stir-welding-technology-for-titanium-58qbturi3z.pdf

Alternative friction stir welding technology for titanium–6Al–4V propellant tanks within the space industry

The article describes the basic concepts for applying the friction stir welding (FSW) process to components made from titanium alloy. As is well known, titanium and its alloys are demanding applications for FSW due to the high mechanical strength, high melting temperature, low thermal conductivity, susceptibility to atmospheric contamination, and the high tendency for embrittlement of the material due to the absorption of interstitial elements (O, N, and H). Hence, the process parameters have great influence on the microstructure and properties of the welded joint. To date, there is no consolidated experience, even at the international level, on the behaviour of the FSW process for titanium alloys; however, this article reports the main results obtained from recent studies in the field and data provided by the Institute further to tests conducted in relation to research projects aimed at the aeronautics sector. In particular, it is pointed out that the use of conventional tools (consisting of ‘Shoulder To...

A. Lauro

Papers

Friction stir welding of titanium alloys