A MICROMECHANISM FOR CRYSTALLIZATION OF AMORPHOUS-ALLOYS .2. BULK CRYSTALLIZATION PROCESS

Bulk crystallization products of amorphous Ni-P alloy were studied by X-ray diffraction and transmission electron microscope (TEM). The crystallization products contain two crystalline phases: body centered tetragonal (bct) Ni3P compound and face centered cubic (fcc) Ni austenite. The orientation relationship between the two phases is <111> bct parallel-to <110> fcc. High resolution electron microscopy (HREM) technique was used to get a detailed observation of the crystal structure. It was found that both the Ni3P and the Ni phase were discontinuous rather than continuous. Very small crystals initially formed in crystallization were found to be composed of even smaller crystalline particles of the two phases. The morphologies and structures of the crystallization products, as well as the crystal formation process were interpreted using a new crystallization micromechanism proposed by the authors in a previous publication.