Metalogram

• Hardness:the easiest attribute to measure but is not sufficient information about a material to find the correct preparation method.
  
• Ductility: the ability of a material to deform plastically and is far more important. How  does a material actually respond to mechanical abrasion? Is it easily deformed, or do we get cracks and pull-outs during preparation?

The Metalogram displays materials according to both hardness and ductility, since both of these are factors in the selection of a preparation method.
For the preparation of materials which cannot be placed easily in the Metalogram, for example composites, coatings or other materials consisting of various phases or components, the following rules can be applied:

• Select a method which is suited for the material's predominant component.
• Check the samples after each step and, if preparation artifacts do occur, consult Metalog Master for advice.
• The most common artifacts connected with the materials above are edge rounding, relief, pull-outs and porosity.

Description of the Metalogram
The x-axis represents the hardness in Vickers. The values are not shown in a linear way because the variety of preparation methods for softer materials is greater than for hard ones. The shape of the Metalogram results from soft materials generally being more ductile and hard materials usually being more brittle.

Selection of a preparation method
First, find the hardness on the x-axis. Then, depending on the material's ductility, either move up or down. Unlike hardness, ductility is not easily defined in precise numbers. Materials must be placed on the y-axis according to your own previous experience. You must have an idea of how a material will perform, that is, whether it is ductile or brittle.

To demonstrate our idea, we have displayed some materials in the Metalogram (see description below). Ten preparation methods are the basis of the Metalogram. Seven methods, A - G, cover the complete range of materials. They are designed to produce specimens with the best possible results. In addition, three short methods, X, Y and Z, are displayed. These are methods for very quick, acceptable results.