Alloys for additive manufacturing: production, processing, design, and sustainability

Learning Outcomes

Subject Specific Intellectual and Research Skills

Having successfully completed this module you will be able to:

• Apply the above to powder-based additive manufacturing
• Understand modern computational thermodynamics concepts
• Leave behind the materials-selection engineering concept to focus on the materials by design concept to apply to new technologies and address sustainability requirements
• Use thermodynamic software to identify phases relevant to alloy behaviour and to relate to properties

Transferable and Generic Skills

Having successfully completed this module you will be able to:

• Apply computational thermodynamics to other engineering fields such as semiconductors or aerospace
• Apply the philosophy of materials design to other additive manufacturing techniques, such as wire-based or binder jetting

Knowledge and Understanding

Having successfully completed this module, you will be able to demonstrate knowledge and understanding of:

• Appreciate the differences in microstructure and properties of additively manufactured builds in comparison to wrought products.
• Appreciate the commercial alloy compositions, key microstructural features, and application of 3D printed Steels, Titanium alloys, Nickel-based superalloys, Aluminum alloys and High-entropy alloys.
• Understand and apply techniques for the modelling the development of novel build microstructures.
• Design sustainable 3D-printed metal components for a prescribed microstructure and performance.
• Appreciate the environmental footprints of additive manufacturing and apply techniques to reduce it.
• Understand and apply principles of alloy and microstructure design for additively manufactures alloys.
• Understand the relationship between process parameters and the build microstructure.
• Understand the principles for processing additively manufactured components with different build techniques.
• Appreciate the production techniques for metallic alloy powder production, the defects and advantages offered by each.
• Understand and apply techniques for the accelerated discovery of new alloys for additive manufacturing.
• Apply a systems engineering approach to transform metal-based 3D printing technology into sustainable.

Subject Specific Practical Skills

Having successfully completed this module you will be able to:

• Simulate metal 3D printing processes
• Perform basic alloy design

Review of powder-based additive manufacturing techniques: Introducing 3D printing techniques such as laser powder bed fusion, laser metal deposition, electron beam melting, and binder jetting, identifying their key processing parameters. Introducing most common powder production methods. Additive manufacturing challenges and applications: Introducing process-induced defects such as cracks, pores, surface roughness, and residual stress, and how printability can be enhanced in terms of the right choice of process parameters and composition. Processing-microstructure-property relationships: Introducing the general microstructural characteristics of builds in terms of temperature gradients, solidification, and solid-solid phase transformations. How to restore the microstructure and the modelling approaches to predict its development. Additive manufacturing of steels: Introducing austenitic, marageing, precipitation hardening stainless, tool and duplex stainless steels, making emphasis on their microstructural hierarchy, strength, ductility, fatigue and wear properties. Additive manufacturing of titanium alloys: Introducing Ti-6Al-4V, commercially pure titanium, and beta titanium alloys with a focus on their thermal behaviour, mechanical properties, anisotropy, and porosity. Additive manufacturing of nickel superalloys: Introducing IN718, IN625, Hastelloy X, and non-weldable nickel superalloys, setting out the challenge for the design of new nickel superalloys. Additive manufacturing of Aluminium alloys: Introducing AlSi10Mg, AlSi12, Scalmalloy, AlSi7Mg and AA6061 alloys with particular attention to their mechanical and fatigue properties. Additive manufacturing of high-entropy alloys: Introducing the Cantor alloy and its aluminium-modified and other variations, as well as refractory high entropy alloys. Sustainability: Introducing the environmental footprints of additive manufacturing in terms of resources required, waste and pollution, and its benefits. The techniques for lifecycle assessment to predict environmental impact before printing; as well as the social impact, life cycle costing and eco-design methodology to conceive new 3D printing processes and alloys. Alloy design for additive manufacturing: Introducing a manufacturing-base alloy design for sustainable additively manufactured alloys adopting optimisation methods (including machine learning), the CALPHAD methodology and combinatorial optimisation.

1. Lectures for the delivery of new material and concepts. 2. Computer laboratories using Thermocalc software. 3. Design project to apply lecture material, computational thermodynamics, and sustainability concepts. The teaching pattern is summarised below. Unit 1 A ten week lecture course consisting of two single (45 min) lectures per week. - Additive manufacturing techniques (weeks 1- 2) - Alloy families (weeks 4 - 8) - Sustainability and alloy design (weeks 9 – 10) Unit 2 A two week laboratory course consisting of five 2 x 45 min computer laboratory sessions (weeks 9 – 10) - Introduction to thermodynamic modelling and Thermocalc software (2 x 45 min lab session) - Relating phase constitution to microstructure to properties and Thermocalc calculations (2 x 45 min lab session) - Exercises on sustainable alloy design (three 2 x 45 min lab sessions)

Formative

This is how we’ll give you feedback as you are learning. It is not a formal test or exam.

Journal

• Assessment Type: Formative
• Feedback:
• Final Assessment: No
• Group Work: No

Summative

This is how we’ll formally assess what you have learned in this module.