Crystallization phases of the Zr41Ti14Cu12.5Ni10Be22.5 alloy after slow solidification

A systematic study was carried out on the equilibrium phases after slow sol idification of the Zr41Ti14Cu12.5Ni10Be22.5, alloy. The crystalline microst ructure of the slowly cooled melt of the alloy shows "polygons" and "plates " embedded in a fine-grained two-component matrix. To analyze the crystal s tructure of the different components, microdiffraction technique combining convergent beam electron diffraction and conventional selected-area electro n diffraction were used. The stoichiometry of these phases was confirmed by field ion microscopy with atom probe and energy-dispersive x-ray analysis in a transmission electron microscope. The polygons were determined to be c ubic (a = 1.185 nm) with space group Fm (3) over bar m (cF116). The plates were found to be tetragonal (a = 0.37 nm, c = 1.137 nm) with space group 14 /mmm (tI6). Its composition is (Cu + Ni)(Zr + Ti),. One phase of the fine-g rained two-component matrix was rich in Ti and poor in Be; the other one wa s rich in Be and poor in Ti. The Ti-rich phase was determined to be hexagon al (a = 0.536 nm, c = 0.888 nm) with space group P6(3)/mmc.