Weldability Of High Strength Aluminum Alloys

This memorandum describes the fusion-welding characteristics, mechanical properties, and stress-corrosion behavior of high-strength, weldable aluminum alloys. These are defined as alloys in which sound welds can be produced and in which at least 50 and 70 percent of the maximum base-metal strength can be retained in the as-welded and post-weld-treated conditions, respectively. Careful selection of joining method and filler metals as well as close control of joining-process parameters is necessary to produce high-strength aluminum weldments. Highest strengths and weld-joint efficiencies in high-strength weldable alloys are achieved with the use of postweld aging and/or mechanical treatments. The best combination of highest strengths and good welding characteristics is found in the 2000 and 7000 alloy series. As compared with the 2000 and 5000 alloy series, the 7000 alloy as a class suffer three major property disadvantages: (1) their tendency to be notch sensitive, (2) their tendency to exhibit low toughness at low temperatures, and (3) their much greater susceptibility to stress-corrosion cracking. Nonetheless, several relatively new 7000 series alloys have been developed which show reasonably good notch toughness to -423 F and which are considered competitive with the 2219 and 2014 alloys for cryogenic applications. (Author).

Friction Stir Welding of High Strength 7XXX Aluminum Alloys is the latest edition in the Friction Stir series and summarizes the research and application of friction stir welding to high strength 7XXX series alloys, exploring the past and current developments in the field. Friction stir welding has demonstrated significant benefits in terms of its potential to reduce cost and increase manufacturing efficiency of industrial products in transportation, particularly the aerospace sector. The 7XXX series aluminum alloys are the premium aluminum alloys used in aerospace. These alloys are typically not weldable by fusion techniques and considerable effort has been expended to develop friction stir welding parameters. Research in this area has shown significant benefit in terms of joint efficiency and fatigue performance as a result of friction stir welding. The book summarizes those results and includes discussion of the potential future directions for further optimization. Offers comprehensive coverage of friction stir welding of 7XXX series alloys Discusses the physical metallurgy of the alloys Includes physical metallurgy based guidelines for obtaining high joint efficiency Summarizes the research and application of friction stir welding to high strength 7XXX series alloys, exploring the past and current developments in the field

The purpose of this report is to summarize the present state of aluminum-welding technology. The major topics covered are: Basic metallurgy of various heat-treatable and non-heat-treatable alloy classes; welding processes used for joining aluminum with emphasis on newer processes and procedures which are considered important in defense metals industries; welding characteristics of various alloys; comparison of tensile properties, cracking tendencies, notch toughness, and stress-corrosion characteristics of various weldments; dissimilar metal welds; and causes of porosity and cracking of aluminum welds and the effect of porosity on weld strength. (Author).

This publication is a comprehensive book on the welding of aluminium, aimed primarily at practising engineers and students of welding technology. After describing the properties of wrought and cast aluminium alloys, their applications, alloy designations and composition, both in heat-treatable and non heat-treatable alloys, it goes on to explain the process variables in weld metal transfer mechanisms, the ways of overcoming problems in GAS tungsten ARC welding, and distortion - also providing numerical methods of analysis. A thorough and timely guide to all aspects of aluminium welding.

This book covers the rapidly growing area of friction stir welding. It also addresses the use of the technology for other types of materials processing, including superplastic forming, casting modification, and surface treatments. The book has been prepared to serve as the first general reference on friction stir technology,. Information is provided on tools, machines, process modeling, material flow, microstructural development and properties. Materials addressed include aluminum alloys, titanium alloys, steels, nickel-base alloys, and copper alloys. The chapters have been written by the leading experts in this field, representing leading industrial companies and university and government research insititutions.

The evolution of mechanical properties and its characterization is important to the weld quality whose further analysis requires mechanical property and microstructure correlation. Present book addresses the basic understanding of the Friction Stir Welding (FSW) process that includes effect of various process parameters on the quality of welded joints. It discusses about various problems related to the welding of dissimilar aluminium alloys including influence of FSW process parameters on the microstructure and mechanical properties of such alloys. As a case study, effect of important process parameters on joint quality of dissimilar aluminium alloys is included.