The total attenuation coefficients are measured for seven alloys at 84 and 145 keV by the transmission method using a good geometry setup employing a NaI(Tl) scintillation spectrometer. The scattering contributions are deduced using the theoretical cross sections taken from the recent literature and are subtracted from the measured total cross sections to get the photoelectric cross sections. Finally, the effective atomic numbers are obtained from the graph of cross section versus the atomic number. Results are compared with semiempirical estimates and are found to be in good agreement. Results are also compared with the available experimental values, some of which are reported at 412 keV and some at 52.5 keV and a good agreement is noted.