Thermomechanical fatigue of solder joints: A new comprehensive test method

Conference · Sun Jan 01 00:00:00 EST 1989

DOI:https://doi.org/10.1109/ECC.1989.77763· OSTI ID:6294785

Frear, D. R.

This paper presents a new comprehensive method to test solder joint in thermomechanical fatigue. The method involves simultaneous imposition of temperature cycles and strain on discrete solder joints in a shear orientation. The stress, microstructure, and number of cycles to failure were monitored. Cycles to failure were determined by a continuous electrical detection method. 60Sn-40Pb and 40Sn-40In-20Pb solder joints were tested using this new method at 20% shear strain. The 60Sn-40Pb alloy has a shorter fatigue lifetime than did 40Sn-40In-20Pb. This is attributed to heterogeneous coarsening that concentrates strain into a small area of the 60Sn-40Pb microstructure. In contrast, the 40Sn-40In-20Pb microstructure becomes refined. The heterogeneous coarsening also results in cyclic softening in 60Sn-40Pb, which was not observed in 40Sn-40In-20Pb. Failures initiated within the coarsened band in 60Sn-40Pb at Sn-Sn grain boundaries or phase boundaries. In contrast, failures initiated at the surface of 40Sn-40In-20Pb joints and propagated through both phases of the microstructure. 41 refs., 16 figs.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6294785
• Report Number(s): SAND-89-0401C; CONF-8905102-1; ON: DE89008045
• Resource Relation: Conference: 39. electronic components conference, Houston, TX, USA, 22 May 1989; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
INDIUM ALLOYS
THERMAL FATIGUE
LEAD ALLOYS
TIN ALLOYS
GRAIN BOUNDARIES
MATERIALS TESTING
MICROSTRUCTURE
SOLDERED JOINTS
STRAINS
STRESSES
ALLOYS
CRYSTAL STRUCTURE
FATIGUE
JOINTS
MECHANICAL PROPERTIES
TESTING
360103* - Metals & Alloys- Mechanical Properties
420500 - Engineering- Materials Testing