you'll get a structural or electronic phase transition if the pressure go on.

Thanks for your answer.

The understanding of the elastic constants could help you to figure out how is changing the material previous to the phase transition. Also, this could be related wit a softening of a phonon mode.

Thanks for your answer.

Dear Dr Md. Atikur Rahman

Usually the Youn's modulus increases with pressure, but sometimes it decreases with increasing pressure, please see for example in: O. Gomis, F.J. Manjón, P. Rodríguez-Hernández, A. Muñoz, Elastic and thermodynamic properties of α-Bi2O3 at high pressures: Study of mechanical and dynamical stability, Journal of Physics and Chemistry of Solids

124 (2019) 111-120 ,

doi: 10.1016/j.jpcs.2018.09.002.