ULTRASONIC ATTENUATION AND VELOCITY STUDIES IN THE α-α SOLID SOLUTION PHASES OF THE Nb-H SYSTEM F.M. Mazzolai et H.K. Birnbaum J. Phys. Colloques, 42 C5 (1981) C5-769-C5-774 DOI: 10.1051/jphyscol:19815119