A synchrotron X-ray radiography study of dendrite fragmentation induced by a pulsed electromagnetic field in an Al–15Cu alloy

In all of metallurgical processing, probably the most prominent example of nucleation control is the “inoculation” of melts to suppress columnar solidification and to obtain fine equiaxed grain structures in the as-cast solid. In inoculation, a master alloy is added to the melt to increase its solute content and to add stable particles that can act as nucleants for solid grains. This is important for alloys of many metals, and in other cases such as ice nucleation in living systems, but inoculation of aluminum alloys using Al–5Ti–1B (wt.%) master alloy is the exemplar. The key elements are (i) that the chemical interactions between nucleant TiB2 particles and the melt ensure that the solid phase (α-Al) exists on the surface of the particles even above the liquidus temperature of the melt, (ii) that these perfect nucleants can initiate grains only when the barrier for free growth of α-Al is surmounted, and (iii) that (depending on whether the melt is spatially isothermal or not) the release of latent heat, or the limited extent of constitutional supercooling, can act to limit the number of grains that is initiated and therefore the degree of grain refinement that can be achieved. We review recent studies that contribute to better understanding, and improvement, of grain refinement in general. We also identify priorities for future research. These include the study of the effects of nanophase dispersions in melts. Preliminary studies show that such dispersions may be especially effective in achieving grain refinement, and raise many questions about the underlying mechanisms. The stimulation of icosahedral short-range ordering in the liquid has been shown to lead to grain refinement, and is a further priority for study, especially as the refinement can be achieved with only minor additions of solute.

Overview: Application of heterogeneous nucleation in grain-refining of metals

This is the first account of the history of modelling dendritic and cellular solidification. While Part I reviewed the progress up to the year 2000 [Kurz W, Fisher DJ, Trivedi R. Progress in modell...

Progress in modelling solidification microstructures in metals and alloys. Part II: dendrites from 2001 to 2018

Heterogeneous nucleation and grain growth of inoculated aluminium alloys: An integrated study by in-situ X-radiography and numerical modelling

Revealing the heterogeneous nucleation behavior of equiaxed grains of inoculated Al alloys during directional solidification

Combined in situ X-ray radiographic observations and post-solidification metallographic characterisation of eutectic transformations in Al–Cu alloy systems

In situ X-radiography solidification experiments were performed on Al-based alloys, using both synchrotron and laboratory-based X-ray sources, in conjunction with a gradient furnace and a newly developed isothermal furnace, respectively. The effect of gas porosity nucleation and growth within the semi-solid mush during both columnar and equiaxed solidification was thereby observed. In all experimental cases examined, gas porosity was observed to nucleate and grow within the field-of-view (FOV) causing various levels of distortion to the semi-solid mush, and thereafter disappearing from the sample leaving no permanent voids within the solidified microstructure. During columnar growth, a single bubble caused severe remelting and destruction of primary trunks leading to secondary fragmentation and evidence of blocking of the columnar front. Equiaxed solidification was performed under microgravity-like conditions with restricted grain motion in the FOV. The degree to which the nucleated gas bubbles affected the surrounding grain structure increased with increasing solid fraction. However, bubble sphericity remained unaffected by apparent solid fraction or grain coherency.

https://iopscience.iop.org/article/10.1088/1757-899X/117/1/012067/pdf

In situ X-ray observations of gas porosity interactions with dendritic microstructures during solidification of Al-based alloys

A course in Metals Processing, delivered to senior engineering students, in which much of the curriculum consists of summaries of selected relevant research projects, is presented. A balanced research team, under the leadership of the course co-ordinator, has designed and delivered an advanced module covering the near net shape processing of metallic alloys. The topics covered include alloy solidification and casting, plasticity and metal forming, and a practical laboratory exercise. Details of the course content, and the research on which much of it is based, are hereby presented, along with commentary on the pedagogic rationale for the approach taken.

/pdf/research-informed-education-in-materials-science-and-1qotuwelm1.pdf

Research-informed Education in Materials Science and Engineering: a Case Study

XRMON‐SOL:結晶粒精製Al‐20wt%Cu合金の等温等軸凝固

In-situ X-ray radiography is currently being used to study solidification processes in a wide range of binary and ternary alloy systems. In this study, thin samples of hypoeutectic Al-Cu alloys were mounted in a Bridgman furnace and solidified near-isothermally from above the liquidus to below the eutectic. The eutectic transformation was easily identified from a contrast difference between the semi-solid mush and the fully solid phase in the field of view (FOV). By virtue of real time in-situ X-ray radiography, and image analysis techniques, it was possible to directly observe and measure eutectic nucleation as well as transformation rate across the FOV. Post-solidified samples were then subjected to further microstructural analysis, whereby the lamellar eutectic spacings were measured at random locations across the FOV region. The lamellar spacings were correlated to the eutectic transformation rate and the results compared to theoretical predictions. Reasonable agreement was observed and some interesting observations are noted, e.g. liquid feeding induced grain motion and the possible precursor to hot tearing.

In-Situ X-Ray Radiographic Observations of Eutectic Transformations in Al-Cu Alloys

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

A.G. Murphy

Author Tools

Chat about Author