It depends on the type of material and the deformation rates. For solids, one often uses tension or compression testing on cylindrical specimens. The deformation is applied and rate is controlled at the ends of the specimen. For fluids, one typically uses simple shearing tests, with material confined between parallel plates or in the annulus between coaxial circular cylinders. All this is the subject of the science of rheology, and there are numerous books and research papers on the subject. 

By heating. You can used high temperature laboratory oven (LHT), play with the temperature values, then at particular temperature analyze the product using FTIR. You also can use the TGA (thermal gravimetric analysis). It will be helpful if You can find the TGA combining with FTIR.

Dear Oluwagbenga 

Your question is quite general one.   The deformation and the materials should be specified in order for one to suggest to you which method is suited for your case.

As regards the answer from Mutrofin, it is not clear how LHT, FTIR and TGA have any thing to do with deformation per se. One must  specify exactly  how this is to be connected to deformation and thermo-rheological behavior. Habib is basically restating what I pointed out, without giving examples of rheological techniques.

. Gleeble is just another way of studying thermomechanical behavior i.e. of "characterizing". The original question did not mention thermal effects. Also, simulation software is for simulating not for characterization. I think we  may have a problem with language, if not logic.

Dear Oluwagbenga 

I wish you reflect a feedback on the above suggestions.

Thanks to everybody for your contributions. I intentd to study deformation behaviour of High Entropy Alloy.

Refer to the following:

Bernd Gludovatz, at al, "A Fracture-Resistant High-Entropy Alloy for Cryogenic Applications",Science 345(6201):1153-1158(2014).

Dear Oluwagbenga,

Deformation behaviour is a big field with plenty of interesting areas. Here are some general ways you could start your study (till you find a particular area that interests you):

(1) Hardness testing : A fundamental test that can give you many indications about your material. Traditional hardness test will give you an idea about how resistant the material is to deformation. Using a micro-indenter, you can check the individual hardness of different microstructural constituents and analyse how they affect overall behaviour.

(2) Tensile testing : You can prepare tensile test specimens (perhaps following the ASTM E8 standard) and perform tension tests. This will give you the yield strength, ultimate strength, toughness and ductility of your material. On a UTM/equivalent machine you can try doing a tension test at different strain rates (different crosshead velocities) and check if your alloy is rate-sensitive.

(3) Compression testing: This can tell you how workable the alloy is, i.e. how easy it is to re-shape it. You could perform tests at room temperature (ASTM E9) to assess cold workability, or at high temperatures (ASTM E209) to assess hot workability. In case of the latter you can try to optimise different temperature-strain rate combinations for good workability. A popular and effective tool for this is the 'processing map' based on Dynamic Materials Model.

(4) Impact test: This is useful to study deformation behaviour at very high strain rates, i.e. at high speeds. It will tell you how 'tough' your alloy is under impact loading. You could consider this for applications where a component will hit objects at high speeds ( I believe high entropy alloys have applications in this regard).

These are some good ways to start; as you go deeper there are plenty more things to do, but those require a more well defined problem. Good luck!

I have the impression that many replies to questions on this web site have been lifted from standard materials-testing handbooks or other such sources. I believe it would be good scientific practice  to cite one's sources, especially when one does not have  much expertise in the techniques in question. Among other things, it might give the questioner the chance to consult the source directly. 

Thanks for your contribution @ Aashranth B and Joe Goddard

Hi.

It is desirable to formulate the question more specifically.

    The deformation in steel produces martensite, if you are doing a thermal treatment on the material, as forging, you must measure your initial and  end of your sample thickness and use the equation to obtain the steel deformation %.

First you have to consider what type of materials you want to consider for your research, ceramics normally evaluated by compressive strength and fracture toughness as an example.

This highly depends on what you mean by study deformation. Most of the suggestion are correctly suggesting mechanical testing and the variations of it. However, when you say deformation this strikes me that you want to investigate failure mechanisms or methods which a structure will deform. In which case there are a wide array of strain based measurements such as digital image correlation, interferometry, X-ray diffraction strain analysis to name a few. Which give a larger insight into deformation when performed in situ to mechanical testing.