Mechanically Induced Atomic Disorder and Phase Transformations

摘要

The study shows the possibilities of preparing alloys in various metastableconfigurations by the simple technique of ball milling. Firstly, chapter 2 gives the description of experimental techniques. In chapter 3, evidence of atomic anti-site disordering in A15-structure superconducting compounds Nb3Sn and Nb3Au during an early stage of milling is demonstrated. Chapter 4 represents the experimental results on the B2-structure magnetic compounds CoGa and CoAl upon mechanical impact. These compounds are well known for their particular type of atomic disorder, namely triple-defect disorder. Various examples of experimental evidence of phase transformations induced by mechanical grinding are presented in chapter 5. Section 5.2 gives an example of amorphization induced by mechanical attrition in the intermetallic compound Ni3Sn. Section 5.3 shows the milling experiment of the intermetallic compound V3 Ga. In section 5.4, for the first time, the observation of a phase transformation to a high-temperature phase with a complex structure will be demonstrated for the intermetallic compound Co3Sn2. In the last chapter, detailed studies on the intermetallic Nb-Au binary compounds for a variety of compositions are presented.