The effect of substrate on the microstructure and creep of eutectic In-Sn

Journal Article · Thu Dec 01 04:00:00 EST 1994 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02649224· OSTI ID:6874779

Goldstein, J L.F. ^[1]; Morris, Jr, J W ^[2]

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1. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering
2. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering Lawrence Berkeley Lab., CA (United States)

This study was conducted in order to determine and understand the effect of substrate on the behavior of eutectic In-Sn. Samples for mechanical testing were produced with either bare Cu or Ni on Cu substrates. Both the microstructure and the mechanical behavior are strongly dependent on substrate. When eutectic In-Sn is joined to bare Cu, Cu diffusion into the joint causes the alloy to become off-eutectic, giving a nonuniform and irregular microstructure. The addition of a layer of Ni acts as a diffusion barrier, preventing Cu diffusion sufficiently such that a uniform, normal colony-based eutectic forms. Deformation is more uniform in the In-Sn on Ni, while it is concentrated along the length of the joint in the In-Sn on Cu. This distinction is reflected in the different shapes of shear stress-strain curves between In-Sn on Cu and In-Sn on Ni. The stress exponents and activation energies for creep also vary with substrate. Creep deformation is governed by the In-rich [beta] phase for In-Sn on Cu and by the Sn-rich [gamma] phase for In-Sn on Ni. If In-Sn on Ni samples are aged, the microstructure coarsens and the mechanical behavior changes to resemble that of the as-cast In-Sn on Cu.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6874779
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 25:12; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360103 -- Metals & Alloys-- Mechanical Properties
ALLOYS
COPPER
CREEP
DATA
ELEMENTS
EXPERIMENTAL DATA
INDIUM ALLOYS
INFORMATION
JOINTS
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
NICKEL
NUMERICAL DATA
SOLDERED JOINTS
TIN ALLOYS
TRANSITION ELEMENTS