I have powder samples, want to analysis mechanical properties in terms of hardness, toughness, yielding point and brittleness. Please suggest me which method will be suitable. As UTM needs rigid flexible samples. will nano indentation suitable? Then how to prepare the samples. Am i moving on right way or not? Is it possible to calculate all these variables from powder?
Thank you
Powder? What size of grain size it is? Usually if we taking about hardness, Young Modulus, Rm, and other properties of materials we have to make measurements at the same condition according to ASTM, ISO or another Standard. Thinking about powder grain and hardness - I cant imagine it :) Maybe nanoindenter (Hysitron) may do some measurement, but Im not sure because of sample mounting problems.
I think you will need to sinter your powders to prepare samples for testing. Find a bench top compression moulding press.
My materials average diameter in range of 20-30 micrometer. I will try from bench top compression method if it has pellet processing.
Thank you
Hi Shatrudhan,
Nanoindentation is not a method to obtain bulk properties. I would recommend trying to process your polymer powders to form a bulk compact and then investigate mechanical properties.
If there is no ready made hot embossing setup, you can build up a customized one in your lab. Use a pair of steel molds that should be machined to produce a cavity in one of it to pour your polymer powder. These steel blocks should also be drilled at appropriate locations in a workshop to add few cartridge heaters and a thermocouple for heating and regulating temperature. These steel blocks can be mounted on a press for carrying out hot embossing experiments. Just check the degradation temperature of your polymer materials and optimize the hot embossing parameters.
Hello,
I think you can use resin molding method for measuring the hardness of a single powder.
- First of all, you have to use a gentle glue for adhesive your powder to the bottom of the mold. (Probable your powder density is lower then resin density. So you should prevent of the floating of your powders in the resin.)
- And add your molding resin. Wait up to dry.
- Then, use a suitable (fine grade) sandpaper up to powder (if possible grind it up to the center point of the powder).
- Now you can find smooth powder surfaces and try microhardness method(s) with low loads.
- And I think you can find or improve a formula/empirical formula for yielding point. (Unfortunately, this means you can find UTS data with theoretically.)
Have a good day.
Hello! By extrusion you can prepare a masterbach, and then inject some samples to test via tensile or flexural analysis.
Hello!
The fact is that the properties that interest you will depend on the technology of manufacturing the samples, their shape and dimensions.
All the best
Nowadays the nanoscale mechanical properties of powders can also be investigated by AFM
Please think about this trend.
Best regards
Sure, Sir but for this we need a seperate TIP for scanning. As I am student it is impossible to purchase it, so I am looking an alternative facility using pellets by nanoindentation as available facility.
Thank you
Shatrudhan,
I have some experience in trying to measure characteristics of spheres of your dimensions. You could try to indent with a flat punch (maybe 100um in diameter). The only problem I can foresee is that your tiny spheres are going to move around (even if you stick it on a double sided tape). To avoid this, you could mount a large amount of the powder and prepare your sample until you reach few nm roughness. This could work, however you will get different values based on the thickness of remaining material at that section and the indentation depth, so you will need to do a good number of indentations and get a distribution.
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