The use of lightweight materials in the production of cryogenic tanks, spacecraft body etc. are becoming the need to develop dissimilar metal FSW joints. Friction stir welding (FSW) is a novel and inspired light metal joining process since it is not involved with the melting of the parent metal. In this work, two Aluminium 7020 plates were welded with Zn as an interlayer, using friction stir welding method. Different joints were made by varying the thickness of interlayer (Zn) and thereafter the characterization is done against mechanical properties and microstructure of weld nugget. The test result shows that the specimen joint with 10µ Zn interlayer has higher mechanical properties than samples made with 5µ, 10µ, 20µ, 40µ and 100µ Zn interlayer. To analyze the cause, further optical studies (Image analyzer and SEM analysis) were carried out and found the interlayer dispersion plays a vital role in weld strength. As a conclusion addition of Zinc interlayer with preferable thickness (10µ) in Al7020 FSW joints improve tensile strength and hardness than the FSW joints made with higher and lower interlayer thickness.

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On-line monitoring of tool wear in turning is vital to increase machine utilization as scrapped components, machine tool breakage and unscheduled downtime result from worn tool usage cause huge economic loss. Several techniques have been developed for monitoring wear levels on the cutting tool on-line. Keeping in to account the difficulties encountered during the implementation of tool condition monitoring (TCM). The signal acquisition is one of the key elements used during the implementation of TCM. This paper provides an in depth coverage of various signal acquisition methods used in TCM.

Purpose: Fuel or oil transmission pipelines are made with light metal alloys to preventcorrosion and to provide a better safety record. This is achieved by the combinationof perfect design, selection of materials and functioning practices. However, like anyengineering structure, these lines also fail occasionally. Major cases of such failure it inducesdue to external interference or corrosion or due to manufacturing defects; so such of defectsif they were detected before failure and that can be treated to avoid failure or the life timecan be improved.Design/methodology/approach: In this study an aluminum alloy sample with microcrack was treated with FSW process with ZN powder. And studies were carried out againstboth treated and untreated samples with cracks.Findings: From the studies it is clear that FSW treatment over surfaces will reduces thecrack initiation in light metal alloy structures. The process can be done before or afterinstallation.Research limitations/implications: The results were recorded and suggested FSW as abest process for crack treatment in Al alloys. Especially in pressure lines or pressure vessels.Originality/value: Friction stir welding (FSW) is a solid-state metal joining process. Thisis energy efficient, ecofriendly, and versatile light metal joining technique. In particular,high-strength aerospace aluminum alloys can be welded by using this technique. This willproduces high harden joints in light metals as just like conventional arc welding techniques.It is considered as the most significant research development in light metal joining.

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