Additive Reinforced Friction Stir Welding of Ultra Lightweight Automotive Structures
Acronym: Ultra Lightweight Automotive
Funding body: Innovate UK
Status: Project
Background
Friction stir processing involves the mechanical stirring of metals using a none consumable tool to join components and/or attain new material properties, including elevated strength. The most common process is friction stir welding (FSW).
The development of lightweight structures is a key priority within the automotive sector in order to meet future CO2 emissions targets. FSW has been adopted by
many original equipment manufacturers as a key enabler of lightweight structures. However, within the UK, the Automotive Council estimates that the combination of new lightweight materials and manufacturing processes such as FSW could be developed further to reduce the mass of a typical family sized car by up to 35 per cent, thereby improving its fuel consumption by 7 per cent for every 150kg reduction in weight.
Objectives
Ultra Lightweight Automotive will investigate new methods of FSW to join automotive body structures made of novel lightweight alloys. The aim is to demonstrate
high strength joints by doping the weld with different grades and concentrations of additives, which may positively influence the structure of the material in the weld and improve strength.
During manufacture, a colloid solution containing different grades and concentrations of additives, such as silica carbide and graphene, will be introduced around the tool interface to achieve additional control over the weld temperature, grain structure and ultimate strength. The project will address four different areas of processing:
• FSW; the joining of both similar and dissimilar aluminium, high strength and magnesium alloys as a means of achieving further lightweighting
• friction stir spot welding with the identified “ideal” welding applied to produce a high strength weld
• the ability of high conductivity additives to aid nondestructive testing of the weld zones
• the ability of friction stir additive processing to produce new functionally graded components.
Benefits
The project will demonstrate an enhanced FSW process capable of joining difficult and/or dissimilar lightweight materials, including aluminium, high strength steels and magnesium alloys, that will also give rise to more durable, stronger and/or lighter joints, for future automotive applications.
Ultra Lightweight Automotive will support the development of novel manufacturing processes, based upon existing UK intellectual property, that will accelerate wider adoption of lightweight automotive structures to help meet future fleet emissions target.