Plasticity fundamentals: using nano-indentation to ‘fingerprint’ point defects in metals
Research into the strength and damage resistance of materials is an internationally “hot” topic, driven by the need to develop stronger, lighter, tougher metallic components. Recent research has shown that small beams/fibres/crystals are stronger and such ‘size-effects’ can change the strength of a material by an order of magnitude. Test size similarly affects the measurement of strength - “smaller is harder”. The ability to vary the test size in nano-indentation and study the interaction with local plasticity has the potential to create new indentation measurement methods that are sensitive to local plasticity length scale and type.
Total indentation hardness response is a function of material yield stress, determined by a combination of the indentation size effect and a material characteristic length scale generated by the frequency of obstacles to dislocation mobility within the material. It is proposed that suitable indentation size effect measurement strategies can be adopted to “fingerprint” the type and density of point defects present in a material. In conjunction with elevated temperature testing, it is also proposed to identify the activation energy of the obstacles present.
The project, therefore, will:
• Establish best practice guidelines for nano-indentation as a materials screening procedure for point defects.
• Evaluate characterization-method-related transferability issues, such as size effects or substrate effects, which must be taken into account in order to obtain equivalent data for materials of different plastic damage.
• Generate guidelines for using new nano-indentation-based methods to identify different types of damage and unravel the superimposing effects of microstructure, size, substrate, graded-layer or pile-up.
This project will investigate the fundamentals of “plasticity size effects” and develop new indentation measurement methods to produce indentation response functions that can “fingerprint” different damage types (e.g. voids, dislocation loops, precipitates, grain boundaries) and distributions (distributed points, or band/layer).
About the Department The Research Institute for Future Transport and Cities has a thriving student community who are integral to the success of the Institute and contribute to our wide-ranging research portfolio.
We take a fresh approach to the challenges facing society by bringing together world-class experts from art and design, human factors, engineering, computer systems and business studies into one focussed Institute. Our work covers automotive, aerospace, maritime and rail transport modes and allows us to take the lead in cross cutting research developing new forms of transport, new forms of manufacturing and new forms of information provision and security. Our research focusses on six key themes:
• Materials & Structures
• Supply Chain
• Business Environment
We have a unique position in UK universities – with over 140 research staff and 120 PhD research students in the Institute capitalising on our links with Coventry City and its status as a European Living Lab for transport and our close collaboration and joint initiatives with major stakeholders.
Candidate Specification Successful applicants will have:
• A minimum of a 2:1 first degree in a relevant discipline/subject area with a minimum 60% mark in the Project element or equivalent with a minimum 60% overall module average, or
• A Masters Degree in a relevant subject area will be considered as an equivalent. The Masters must have been attained with overall marks at merit level (60%). In addition, the dissertation or equivalent element in the Masters must also have been attained with a mark at merit level (60%).
• The potential to engage in innovative research and to complete the PhD within a prescribed period of study
• English language proficiency (an overall minimum Academic IELTS score of 7.0 with a minimum of 6.5 in each of the four components).
• An experimentalist, preferably with some experience of equipment or instrumentation development
• Degree level understanding of materials science; especially the structure and strength of materials
• Basic computer coding and/or modelling/simulation skills
Application Procedure Application information can be found in our how to apply section. Before completing the application please contact [[Email Address Removed]] for an initial informal discussion about the opportunity.
Duration of study: Three years six months fixed term
Application date: This opportunity will only remain open until a suitable candidate is identified- early application is therefore advised. Standard University research application closing dates apply http://www.coventry.ac.uk/research/research-students/application-dates/
£15,000 bursary plus tuition fees - UK/EU/International