The method of calculating the invariant line in HCP→BCC precipitation based on the invariant line strain model is described. The experimentally determined crystallographic features of the lath-shaped or needle-like precipitates formed in the HCP→BCC precipitations occurring in Mg?Al and Zr?Nb alloys were found to be in excellent agreement with the predictions from the model, thus suggesting that the model is valid for predicting the crystallography of diffusion-controlled phase transformations.
