TRANSMISSION ELECTRON-MICROSCOPY ON THE PROCESS OF MECHANICAL ALLOYING IN NI-TI BINARY-SYSTEMS

In this paper, the Ni and Ti powder mixture with equiatomic ratio was high energy ball milled and then consolidated by explosive compaction. The microstructures of as-compacted and heat treated bulk samples aft er explosive consolidation are investigated in detail by transmission electron microscopy (TEM) and high resolution electron microscopy (HRE M). The experiment results reveal the microstructure variation during mechanical alloying in Ni-Ti binary systems. It is found that a metast able phase denoted as I phase formed during ball milling and the struc ture of I phase was determined by both electron diffraction and HREM. Finally, the mechanism of amorphization induced by ball milling was di scussed.