Propagation of macroscopic phase boundaries under impact loading

The phenomena and rules for one-dimensional propagation of macroscopic phase boundary in shape memory alloys (SMA) under dynamic loading were investigated analytically and numerically with a simple mixture model of phase transformation proposed earlier. The interaction between stress waves and phase boundaries (and/or phase transition waves) yielded the complex wave patterns in x–t diagram. The phase boundary responses both for shape memory effect (SME) and pseudo-elastic effect (PE) of SMA were investigated. For SME, it was found to be very interesting that functionally graded material (FGM) might form during the unloading process. For PE, it was found that there existed three basic types of discontinuous interfaces. The interactions among the steady interfaces, the stress waves and the moving phase boundaries might cause some novel phenomena regarding unloading phase boundaries, such as bifurcation and acceleration of the unloading phase boundaries.