Dear Ahmed,

I would recommend to read the fundamental papers by Fred Lange Transformation toughening Part 1-5 J. Mat. Sci. 17 (1982) pages 225 and following.

As Yuri said the transformation depends on the gibbs energy, the surface energy and the strain energy associated with the transformation.

This interdependency is nicely visualized in Figure 5 of Kelly&Rose, Prog. Mat Sci Eng, 47(2002) 463-557.

In ZTA the grain size the constraint of the matrix, the grain form and grain location are important.

best regards

Frank

You can induce stress into a cavity via pressurization.

Ahmed Saleh As you write yourself, your zirconium may be in a stable and unstable state. When stretched, the unstable form turns into a stable one. Therefore, the visible driving force is mechanical action. The stable c form is achieved at constant temperature and pressure when the thermodynamic system reaches its minimum Gibbs energy. The system's drive to minimize the Gibbs energy is the invisible driving force behind achieving a steady state. The diamond on the lady's neck is in an unstable state. The diamond is stable at high temperature and pressure.

Dear Ahmed,

I would recommend to read the fundamental papers by Fred Lange Transformation toughening Part 1-5 J. Mat. Sci. 17 (1982) pages 225 and following.

As Yuri said the transformation depends on the gibbs energy, the surface energy and the strain energy associated with the transformation.

This interdependency is nicely visualized in Figure 5 of Kelly&Rose, Prog. Mat Sci Eng, 47(2002) 463-557.

In ZTA the grain size the constraint of the matrix, the grain form and grain location are important.

best regards

Frank