I am aware of the following figure (see attached image) where grains are clasified as hard and soft depending on their location on the IPF map. It seems that this is also true for BCC crystals as well. What is the reason behind this? I am just trying to understand the reason behind it. I can understand the relationship between the angle of the slip system and the loading axis. But how do we move as in this case to the crystal axis, directions etc?
Hi Panos:
1) For your attached figure, the center of IPF shows softer behavior because only single slip system is operated, while in other regions multiple slip systems are activated.
2) The soft or hard orientation mentioned here are concluded based on actual measured values (such as yield stress), which is different from the soft or hard orientation based on the m value determined by Schmid law.
3) For BCC metals, we donot use such IPF figure due to the fact the BCC metals are easy to slip on multiple slip systems.
Best,
xinfu
Take EBSD scan and then do PICO-Indentation of same area to quantify your relation of hardness with orientation in IPF map.
soft grains are oriented along their easy slip system so it is important to know about loading direction.