I want to compare strength of a metal before and after heat treatment, to assess to effectiveness of that treatment. (See my previous question, Aluminium softened by brazing. How to harden?).
Specifically, I want to find the yield point (the strain a material can take without being deformed, ie the range where it remains elastic).
I have two ideas that use a similar setup. Shove a length of material (constant width, height, length, shape) in a vice. Apply a force to the end. Fasten a $1 digital luggage scale to the other end. Hang a container of water or sand, adding a little each time. Deflection could be measured as the distance from that end to some reference point with a digital caliper.
- Apply an increasing force, until the force is no longer proportional to the deflection (since up till the yield point, materials bend according too hooke's law). Or,
- Apply a force and release. Repeat with increasing forces until the material no longer returns to its original shape.
The problem is, to achieve any real accuracy, both 1 and 2 above would involve 10's of manual iterations per assessment.
Besides buying or hiring a rheometer, are there any practical alternatives?