The positron annihilation parameters of CuZnAl alloys with different e/a

The alloys of Cu--Zn--Al having different electron/atom ratios (e /a) exhibit different ordered phases in the parent phase and stacking faults in the martensite phase, which will affect the ultimate behavior of the shape memory effect. Cu--Zn--Al shape memory alloys formed by rapid solidification have a linear relation between quenched-in vacancy concentration and electron /atom ratio. The alloys were melted from commercially pure Cu, Zn and Al in a non-vacuum furnace to obtain master alloys, which were remelted to give ribbons by the melt spinning technique. Eleven alloys were used and samples were cut from the ribbons. The system of Doppler broadening measurements employed a solid state detector of highly pure Ge. Sandwiched NaCl positron source has an activity of about 2.5 x 10 exp 5 Bq. The measured Doppler broadened two photon annihilation spectra were characterized by an S-lineshape parameter defined as the number of the counted in the central part divided by the counts in the wing areas. Graphs. 9 ref.--A.R.