Effects of Grain Boundary Sliding on Microstructural Evolution and Damage Accumulation in Tin-Lead Alloy

2002 ◽  
Author(s):  
Y.-L. Shen ◽  
K. C. R. Abell ◽  
S. E. Garrett
Keyword(s):  
Grain Boundary ◽  
Solder Joints ◽  
Micromechanical Model ◽  
Grain Boundary Sliding ◽  
Mechanical Effect ◽  
Primary Objective ◽  
Atomic Diffusion ◽  
Lead Alloy ◽  
Cyclic Shear ◽  
Boundary Sliding

Experiments on the eutectic tin-lead alloy were conducted to study the effects of grain boundary sliding on the deformation and damage processes at the microscopic level. The primary objective is to gain mechanistic understandings of solder joint reliability in microelectronic packaging. Bulk specimens were subject to relatively fast deformations of tension, compression and bending, for the purposes of examining the pure mechanical effect without the influence of diffusion related phenomena. Grain realignment and phase redistribution were characterized by microscopy and microhardness indentation. A micromechanical model is proposed to elucidate the observed microstructural changes and progressive damage. This study illustrates the significance of damage in the form of microscopic heterogeneity caused by grain boundary sliding. It also illustrates the possibility of mechanically induced phase coarsening in actual solder joints. High-frequency cyclic shear tests on tin-lead solder joints showed damage along the coarsened band after only a short time, in accord with the proposed effects. Boundary sliding without the influence of atomic diffusion plays an essential role in fatigue damage in solder.

The microstructure of Sn in near-eutectic Sn–Ag–Cu alloy solder joints and its role in thermomechanical fatigue

2004 ◽  
Vol 19 (6) ◽  
pp. 1608-1612 ◽  
Author(s):  
Donald W. Henderson ◽  
James J. Woods ◽  
Timothy A. Gosselin ◽  
Jay Bartelo ◽  
David E. King ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Solder Joints ◽  
Fatigue Crack Initiation ◽  
Grain Boundary Sliding ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Alloy Solder ◽  
Boundary Sliding ◽  
Solder Joint Fatigue ◽  
And Diffusion

During the solidification of solder joints composed of near-eutectic Sn–Ag–Cu alloys, the Sn phase grows rapidly with a dendritic growth morphology, characterized by copious branching. Notwithstanding the complicated Sn growth topology, the Sn phase demonstrates single crystallographic orientations over large regions. Typical solder ball grid array joints, 900 μm in diameter, are composed of 1 to perhaps 12 different Sn crystallographic domains (Sn grains). When such solder joints are submitted to cyclic thermomechanical strains, the solder joint fatigue process is characterized by the recrystallization of the Sn phase in the higher deformation regions with the production of a much smaller grain size. Grain boundary sliding and diffusion in these recrystallized regions then leads to extensive grain boundary damage and results in fatigue crack initiation and growth along the recrystallized Sn grain boundaries.

Examination of Fracture Interfaces in Silicon Nitride

1975 ◽  
Vol 33 ◽  
pp. 60-61
Author(s):  
Nancy J. Tighe
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Slow Crack Growth ◽  
Ceramic Materials ◽  
Grain Boundary Sliding ◽  
Boundary Phase ◽  
Turbine Engines ◽  
Boundary Sliding

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.

INTERNAL FRICTION PEAKS CONNECTED WITH GRAIN BOUNDARY SLIDING IN Al

1983 ◽  
Vol 44 (C9) ◽  
pp. C9-759-C9-764
Author(s):  
E. Bonetti ◽  
A. Cavallini ◽  
E. Evangelista ◽  
P. Gondi
Keyword(s):  
Internal Friction ◽  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
Boundary Sliding
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