TEM and synchrotron X-ray study of the evolution of phases formed during bonding of IN718/Al/IN718 couples by TLPB

BARRIOBERO-VILA, PERE; TOLLEY, ALFREDO; WEISER, ADAM; BOERI, ROBERTO; REQUENA, GUILLERMO; POLETTI, CECILIA; SCHELL, NORBERT; SOMMADOSSI, SILVANA; POLISERPI, MARIANA; GARCÍA, LAURA NOEL; VOJTEK, TOMÁ?; STARK, ANDREAS

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE

SPRINGER

Lugar: Berlin; Año: 2021 vol. 52 p. 1382 - 1394

1073-5623

This study investigates the microstructure across the interconnection zone of IN718 / Al / IN718 23 couples obtained by the Transient Liquid Phase Bonding (TLPB) process at temperatures 24 ranging from 800°C to 1000°C. The crystal structure and the chemical composition of the 25 phases formed, including the AlNi intermetallic, were evaluated using TEM-EDS. The evolution 26 of the AlNi layer as a function of bonding time was studied by in-situ high energy synchrotron 27 X-ray diffraction. The AlNi lattice parameter increases up to 2.9401 Å and subsequently 28 decreases with the annealing time due to changes in the chemical composition of AlNi. This 29 behavior is related to the formation of two distinct layers of AlNi: Al-rich AlNi and Ni-rich 30 AlNi. The split of the AlNi phase indicates that a chemical partition takes place when Ni and Al 31 atomic concentrations are approximately equal. The growth kinetics of both layers are 32 controlled by diffusion with different growth rate constants. These results contribute to the 33 understanding of the solid-state transformations occurring in a multicomponent and 34 multilayered TLP bond under isothermal conditions.