An Essential Role of Crystal Lattice Misfit on Critical Size of Coherent Precipitates in Metallic Materials

In order to understand an essential role of crystal lattice misfit on the critical size of coherent precipitates in metallic materials, the critical size were studied using a method newly developed by the author, which was tentatively called “Different Lattice Misfit Accumulating Method”. The relationship critical size and lattice misfit of coherent precipitates were made clear by this method. In detail, the critical size of coherent precipitates was determined just before the accumulation value of difference (|ap-a0|) of lattice misfit had approached to be a half of the lattice size (1/2a0, just before the generation of the misfit dislocation) of the matrix. The critical size of the coherent precipitates can be described as follows. Y(Critical size of coherent phase) × (|ap-a0|)=1/2a0, and Y(Critical size of coherent phase)=50/X(Lattice misfit ratio, %)