Material property charts
What is a Material Property Chart?
There are a lot of materials, and each has a lot of properties. We need a good way to display and compare them. A useful method of doing this is by plotting them as Material Property Charts, sometimes called ‘bubble’ or ‘Ashby’ charts, with one property on one axis and another property on the other. Each material has a range of values for each property, depending on the exact composition, grade, heat treatment, supplier etc. The materials are represented on the chart as ellipses or ‘bubbles’, whose width and height are determined by the range of the value of the properties.
The range of the axes on the charts is chosen to include all materials, from dense, stiff and strong metals like tungsten to light and flexible polymer foams. This huge range is covered by using logarithmic (‘log’) scales, where each major step on the axes represents a factor of 10. You will see that materials group together, with all the ceramics, for example, having similar values. The first chart above shows the different material families and how they group together.
These charts can be used in many different ways. First of all, they are beautiful and encourage exploration. In CES EduPack they are interactive and enable you to find out more about a property or material. They can also be used to identify gaps where new materials would be useful. They can be used to perform materials selection for new designs or to substitute a material in an already popular product. They can be used for comparing and estimating data. They can also be used to identify trends in properties, including how processing affects properties, and the relationships between them, in a highly visual way.
The charts in this collection are among the most useful. There are many more. You can make and explore your own charts using CES EduPack. Examples of the many ways in which they can be used can be found in the text “Materials Selection in Mechanical Design” 5th edition, Butterworth Heinemann (2017) (ISBN 978-0-08-100599-6).
Mike Ashby’s favourite charts
These charts draw on Granta’s library of materials property data and the material property chart methodology developed by Professor Mike Ashby. They are free to use on websites and in publications when accompanied by the reference “Chart created using CES EduPack 2018, Granta Design Ltd.”
A word of caution. The data on the charts are approximate: they typify each class of material (stainless steels, or polyethylenes, for instance), but within each class, there is considerable variation. They are adequate for the broad comparisons required for conceptual design, and, often, for the rough calculations of embodiment design. THEY ARE NOT APPROPRIATE FOR DETAILED DESIGN CALCULATIONS. Every effort has been made to ensure the accuracy of the data shown on the charts. No guarantee can, however, be given that the data are error-free, or that new data may not supersede those given here. The charts are an aid to creative thinking, not a source of numerical data for precise analysis.