Some Effects of Water Immersion on the Mechanical Behavior of a Polyimide Film

1994 ◽  
Vol 116 (4) ◽  
pp. 317-319 ◽  
Author(s):  
B. D. Harper ◽  
J. M. Rao
Keyword(s):  
Time Dependence ◽  
Mechanical Behavior ◽  
Room Temperature ◽  
Water Immersion ◽  
Polyimide Film ◽  
Experimental Results ◽  
Stress Strain ◽  
Strain Behavior ◽  
Temperature Creep ◽  
Room Temperature Creep

Absorbed moisture is generally thought to have a plasticizing effect upon the mechanical behavior of polymers. This paper presents some experimental results illustrating the effects of water immersion upon the room temperature creep and stress-strain behavior of a polyimide film. It is shown that immersion in water results in antiplasticization as demonstrated by a significant increase in stiffness and decrease in time dependence. These effects were found to be reversible following thermal conditioning at 300°C.

Mechanical Characterization of Assemblies Bonded With Pressure-Sensitive Adhesives (PSAs)

2015 ◽  
Author(s):  
Hao Huang ◽  
Abhijit Dasgupta ◽  
Ehsan Mirbagheri ◽  
Srini Boddapati
Keyword(s):  
Mechanical Behavior ◽  
Failure Modes ◽  
Mechanical Characterization ◽  
Bonding Temperature ◽  
Process Conditions ◽  
Second Phase ◽  
Loading Conditions ◽  
Stress Strain ◽  
Strain Behavior ◽  
Pressure Sensitive

The focus of this paper is on the stress-strain behavior and creep response of a pressure-sensitive adhesive (PSA) with and without carrier layers. This study consists of two phases. The first phase focuses on understanding of the effects of fabrication profiles, including bonding pressure, bonding temperature, bonding time, and aging time, on the PSA joint strength. This part of the study is used to identify an acceptable bonding and aging conditions for manufacturing a robust PSA bonded assembly. Specimens fabricated with this selected set of bonding process conditions are then used for mechanical characterization. The second phase focuses on the assembly’s mechanical behavior (stress-strain behavior and the creep curves) under different loading conditions, including loading stress, loading rate, and loading temperature. The mechanical behavior of PSA bonded assemblies is affected not only by the loading conditions, but also by the assembly architecture. The mechanical behaviors and failure modes of PSAs with and without carrier layers are compared. The reasons for these differences are also discussed.

scholarly journals Room-Temperature Creep Behavior and Activation Volume of Dislocation Nucleation in a LiTaO3 Single Crystal by Nanoindentation

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1683 ◽  
Author(s):  
Yi Ma ◽  
Xianwei Huang ◽  
Yuxuan Song ◽  
Wei Hang ◽  
Taihua Zhang
Keyword(s):  
Creep Deformation ◽  
Room Temperature ◽  
Activation Volume ◽  
Rate Sensitivity ◽  
Dislocation Nucleation ◽  
Orientation Effect ◽  
Plastic Behavior ◽  
Mechanical Heterogeneity ◽  
Temperature Creep ◽  
Room Temperature Creep

The crystal orientation effect on mechanical heterogeneity of LiTaO3 single crystals is well known, whilst the time-dependent plastic behavior, i.e., creep is still short of understanding. Relying on nanoindentation technology, we systematically studied room-temperature creep flows at various holding depths (100 nm to 1100 nm) in three typical orientations namely the X-112°, Y-36° and Y-42° planes. Creep resistance was much stronger in the X-112° plane than the others. In the meanwhile, creep features were similar in the Y-36° and Y-42° planes. The orientation effect on creep deformation was consistent with that on hardness. The nanoindentation length scale played an important role in creep deformation that creep strains were gradually decreased with the holding depth in all the planes. Based on strain rate sensitivity and yield stress, the activation volumes of dislocation nucleation were computed at various nanoindentation depths. The activation volumes ranged from 5 Å3 to 23 Å3 for the Y-36° and Y-42° planes, indicating that a point-like defect could be the source of plastic initiation. In the X-112° plane, the activation volume was between 6 Å3 and 83 Å3. Cooperative migration of several atoms could also be the mechanism of dislocation activation at deep nanoindentation.

Room Temperature Creep Behaviour of Ramming Paste Baked at Different Temperatures

2014 ◽  
pp. 1221-1226 ◽  
Author(s):  
Pierre-Olivier St-Arnaud ◽  
Donald Picard ◽  
Houshang Alamdari ◽  
Donald Ziegler ◽  
Mario Fafard
Keyword(s):  
Room Temperature ◽  
Creep Behaviour ◽  
Temperature Creep ◽  
Different Temperatures ◽  
Room Temperature Creep

A thermally activated model for room temperature creep in nanocrystalline Au films at intermediate stresses

2013 ◽  
Vol 68 (8) ◽  
pp. 551-554 ◽  
Author(s):  
Nikhil Karanjgaokar ◽  
Fernando Stump ◽  
Philippe Geubelle ◽  
Ioannis Chasiotis
Keyword(s):  
Room Temperature ◽  
Thermally Activated ◽  
Temperature Creep ◽  
Room Temperature Creep
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