A5013200604- Additive Manufacturing and 3D Printing Technologies
- Additive Manufacturing Materials and Processes
- Manufacturing Process and Optimization
- Titanium Alloys Microstructure and Properties
- Cellular and Composite Structures
- Injection Molding Process and Properties
- Advanced optical system design
- Welding Techniques and Residual Stresses
- Advanced X-ray and CT Imaging
- High Entropy Alloys Studies
- Metal and Thin Film Mechanics
- Planetary Science and Exploration
- Advanced materials and composites
- Anatomy and Medical Technology
- Space Satellite Systems and Control
- Adaptive optics and wavefront sensing
- Concrete and Cement Materials Research
- Laser and Thermal Forming Techniques
- Orthopaedic implants and arthroplasty
- Magnesium Oxide Properties and Applications
- Laser Material Processing Techniques
- Space Exploration and Technology
- Innovations in Concrete and Construction Materials
- Powder Metallurgy Techniques and Materials
- SARS-CoV-2 and COVID-19 Research
University of Edinburgh
2021-2024
Liverpool John Moores University
2019-2021
University of Liverpool
2021
University of Sheffield
2015-2020
University of Manchester
2012-2017
Selective Electron Beam Melting (SEBM) is a promising powder bed Additive Manufacturing technique for near-net-shape manufacture of high-value titanium components. However without post-manufacture HIPing the fatigue life SEBM parts currently dominated by presence porosity. In this study, size, volume fraction, and spatial distribution pores in model samples have been characterised 3D, using X-ray Computed Tomography, correlated to process variables. The average fraction (< 0.2%) was measured...
Without post-manufacture HIPing the fatigue life of electron beam melting (EBM) additively manufactured parts is currently dominated by presence porosity, exhibiting large amounts scatter. Here we have shown that size and location these defects crucial in determining EBM Ti-6Al-4V samples. X-ray computed tomography has been used to characterise all pores samples prior testing follow initiation growth cracks. This shows stage comprises a fraction (>70%). In initiating defect was often some...
X-ray computed tomography has been used to track the behaviour of individual pores found in selective electron beam melted additive manufactured titanium. Porosity was shrink below detection limit microtomography (< 5 μm) upon hot isostatic pressing. Spherical argon containing gas pores, which have a high internal pressure following pressing, progressively reappear and grow proportion their original as-built size during temperature (β-anneal) treatments, whereas larger irregular low did not...
Abstract Ti-6Al-4V parts, produced by selective electron beam melting additive manufacturing, have been studied X-ray computed tomography (XCT) to track pore closure during a standard hot isostatic pressing (HIPing) cycle. Comparison of repeated XCT scans before and after HIPing, on worst-case samples with different geometries, confirmed that all internal porosity was shrunk below the resolution limit equipment used (~5 µm) following HIPing cycle, apart from defects surface connected ligaments.
The additive manufacturing of metals requires optimisation to find the melting conditions that give desired material properties. A key aspect is minimising porosity forms during process. corresponding analysis pores different types (e.g. lack fusion or keyholes) therefore desirable. Knowing form under thermal allows greater insight into In this work, two pore classification methods were trialled: unsupervised machine learning and defined limits. These applied 3D data from X-ray computed...
Electron Beam Melting (EBM) as a means of Additive Manufacturing (AM), is interest for the fabrication intricate geometries cellular materials in areas where complex architectures are needed, e.g. biomedical implants. Most studies have focused on specific and so effect structure mechanical performance not well understood. Many kinds micro- macro-scale defects can arise additively manufactured components, assessment their influence properties needed. In this work, lattices Ti-6Al-4V having...
Intelligent application of materials with site-specific properties will undoubtedly allow more efficient components and use resources. Despite such being ubiquitous in nature, human engineering structures typically rely upon monolithic alloys discrete properties. Additive manufacturing, where material is introduced bonded to sequentially, by its very nature a good match for the manufacture changes property built-in. Here, some recent progress additive manufacturing spatially varied reviewed...
The Electron Beam (EBM) additive manufacturing process is well suited to fabricating complex structural designs in Ti–6Al–4V because of the design freedoms it offers combined with strong and consistent material properties. However has been observed that complications may arise when truss-like structures (such as those produced via topology optimization) form undersized features on finished part. issue appears affect truss members are not aligned vertical build direction, an apparent lack...
Abstract Metal powder-bed fusion additive manufacturing technologies offer numerous benefits to the industry. However, current approach printability analysis, determining which components are likely build unsuccessfully, prior manufacture, is based on ad-hoc rules and engineering experience. Consequently, allow full exploitation of manufacturing, there a demand for fully systematic problem. In this paper we focus impact geometry in analysis. For first time, detail machine learning framework...
Abstract This study investigates the influence of surface finish and post-processing conditions on mechanical properties 17-4 PH stainless steel (SS) produced using atomic diffusion additive manufacturing process (ADAM). Diverse sample orientations, including horizontal (0°), 30°, 60°, vertical (90°), were examined, with selected samples undergoing through machining, polishing, heat treatment. Tensile strength testing, roughness measurement, hardness measurement conducted to assess effect...
Abstract Metallic powder bed additive manufacturing is capable of producing complex, functional parts by repeatedly depositing thin layers particles atop each other whilst selectively melting the corresponding part cross-section into layer. A weakness with this approach arises when overhanging features, which have no prior melted material directly beneath them. This due to lower thermal conductivity relative solid material, as a result leads an accumulation heat and thus distortion. The...
Abstract A methodology has been demonstrated to consolidate Ti-6Al-4V powder without taking it the liquid state by novel combination of electron beam melting additive manufacture and hot isostatic pressing processes. This results in improved static mechanical properties (both strength yield) comparison standard EBM processed material. In addition, ability generate microstructurally graded components generating a component with significant change both microstructure properties. is revealed...
This paper details analytical research results into a novel geopolymer concrete embedded with glass bubble as its thermal insulating material, fly ash precursor and combination of sodium hydroxide (NaOH) silicate (Na2SiO3) alkaline activator to form system. The workability, density, compressive strength (per curing days), water absorption the sample loaded at 10% (loading level determined satisfy minimum requirement load-bearing structure) were 70 mm, 2165 kg/m3, 52.58 MPa (28 54.92 (60...
Commercially available 316L (1.4404) stainless steel is commonly used for industrial filtration due to its combination of good material properties, particularly corrosion resistance, which a critical factor filters in corrosive (e.g., saltwater) environments. Recently, laser powder bed fusion (LPBF) has enabled new more complex and efficient pieces be manufactured from this material. However, it know how the resistance affected by manufacturing strategy. Here, LPBF compared with wrought...
Fused filament fabrication (FFF), also known under the brand name fused deposition modelling, has recently emerged as a more straightforward and economic alternative to established 3D printing or additive manufacturing technologies such powder bed fusion for metal part manufacturing. In this work, we report on possible approaches measurements of FFF sintering shrinkage rates from X-ray computed tomography (XCT) data, with particular focus those that use greyscale are thus independent any...
Metallic lattice structures intentionally contain open porosity; however, they can also unwanted closed porosity within the structural members. The entrained and defects three different geometries of Ti-6Al-4V lattices, fabricated by Selective Electron Beam Melting (SEBM), is assessed from X-ray computed tomography (CT) scans. results suggest that horizontal struts are built upon loose powder show particularly high (~20 × 10−3 vol %) levels pores, as do nodes at which many (in our case 24)...
Abstract X-ray computed tomography (XCT) offers a promising non-destructive method to assess high value components that are additively manufactured (AM) for space-based imaging. However, AM can be often challenging measure and the true resolution of XCT system used is both non-trivial determine may change locally. To solve this, we precision micro-machining manufacture cylindrical reference pin with internal holes. This then inserted into any component via subtractive machining, prior...
Abstract The lower capital and running cost of the Markforged Metal X™ platform, in comparison to competing metal additive manufacturing systems, makes it a highly attractive proposition for several industries. unusual print, then sinter, process also has potential avoid many metallurgy issues that can arise using more typical manufacturing, which relies on melting bind material. However, mechanical properties material produced must be well understood. In this paper, 17-4PH stainless steel...
Additive manufacturing (AM; 3D printing) in aluminium using laser powder bed fusion provides a new design space for lightweight mirror production. Printing layer-by-layer enables the use of intricate lattices mass reduction, as well organic shapes generated by topology optimisation, resulting mirrors optimised function opposed to subtractive machining. However, porosity, common AM defect, is present printed and it result printing environment being either too hot or cold, gas entrapped...