Characterization of strain rate sensitivity in pharmaceutical materials using indentation creep analysis

2013 ◽  
Vol 442 (1-2) ◽  
pp. 13-19 ◽  
Author(s):  
Jeffrey M. Katz ◽  
Ira S. Buckner
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Indentation Creep ◽  
Creep Analysis ◽  
Pharmaceutical Materials

The strain-rate sensitivity of the hardness in indentation creep

2007 ◽  
Vol 22 (4) ◽  
pp. 926-936 ◽  
Author(s):  
A.A. Elmustafa ◽  
S. Kose ◽  
D.S. Stone
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Hertzian Contact ◽  
Indentation Creep ◽  
Proportionality Factor ◽  
Element Analysis ◽  
Elastic Deformations ◽  
The Relationship

Finite element analysis is used to simulate indentation creep experiments with a cone-shaped indenter. The purpose of the work is to help identify the relationship between the strain-rate sensitivity of the hardness, νH, and that of the flow stress, νσ in materials for which elastic deformations are significant. In general, νH differs from νσ, but the ratio νH/νσ is found to be a unique function of H/E* where H is the hardness and E* is the modulus relevant to Hertzian contact. νH/νσ approaches 1 for small H/E*, 0 for large H/E*, and is insensitive to work hardening. The trend in νH/νσ as a function of H/E* can be explained based on a generalized analysis of Tabor’s relation in which hardness is proportional to the flow stress H = k × σeff and in which the proportionality factor k is a function of σeff/E*.

scholarly journals Tensile characterization of a lead alloy: creep induced strain rate sensitivity

2019 ◽  
Vol 744 ◽  
pp. 365-375 ◽  
Author(s):  
Luigi M. Viespoli ◽  
Audun Johanson ◽  
Antonio Alvaro ◽  
Bård Nyhus ◽  
Alberto Sommacal ◽  
...  
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Lead Alloy ◽  
Tensile Characterization

scholarly journals Depth-Sensing Indentation Creep Behavior of Nanostructured Thermal Barrier Coatings from As-Synthesized t’-8YSZ Feedstocks

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 38
Author(s):  
Feifei Zhou ◽  
Min Liu ◽  
Yaming Wang ◽  
You Wang ◽  
Chunming Deng
Keyword(s):  
Strain Rate ◽  
Thermal Barrier Coatings ◽  
Strain Rate Sensitivity ◽  
Creep Behavior ◽  
Rate Sensitivity ◽  
Indentation Creep ◽  
Thermal Barrier ◽  
Depth Sensing ◽  
Barrier Coatings ◽  
Nano Indentation

Nano-indentation is a popular method to characterize the micromechanical properties of nanostructured 8YSZ coatings. However, little research has focused on the creep behavior of nano-indentation and only the elastic modulus and nanohardness have been analyzed. Herein, for the first time, the nano-indentation creep behavior of plasma-sprayed nanostructured 8YSZ coatings using as-prepared nanostructured non-transformable tetragonal (t’) feedstocks was investigated. The indentation creep behavior can be well characterized by the power-law equation and the strain rate sensitivity has been calculated in light of the equation. The strain rate sensitivity was sensitive to the load and the reasons were analyzed in detail. The current results can further guide and design thermal barrier coatings from the point of indentation creep property.

Nanoindentation Characterization of Intermetallics Formed at the Lead-Free Solder/Cu Substrate Interface

2010 ◽  
Vol 654-656 ◽  
pp. 2446-2449
Author(s):  
Hideaki Tsukamoto ◽  
Zhi Gang Dong ◽  
Han Huang ◽  
Tetsura Nishimura ◽  
Kazuhiro Nogita
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Structural Integrity ◽  
Activation Volume ◽  
Mechanical Performance ◽  
Rate Sensitivity ◽  
Cu Substrate ◽  
Substrate Interface ◽  
Free Solder

The intermetallics of Cu6Sn5 that are formed at the Sn-based solder/ Cu substrate interface play a significant role in solder joint reliability. The characterization of the mechanical properties of the interface Cu6Sn5 is essential to understand the mechanical performance and structural integrity of the solder joints. In this study, the interface Cu6Sn5 and (Cu,Ni)6Sn5 formed in Sn-Cu and Sn-Cu-Ni ball grid array (BGA) joints were investigated using nanoindentation. The results demonstrated that the strain rate sensitivity and the activation volume of these intermetallics were affected by the reflow times and load conditions. The strain rate sensitivity of Cu6Sn5 and (Cu,Ni)6Sn5 were estimated from 0.023 to 0.105, and the activation volume of Cu6Sn5 and (Cu,Ni)6Sn5 were estimated from 0.128 b3 to 0.624 b3 (b=4.2062x10-9 m) for 1, 2 and 4-reflowed Sn-Cu (-Ni) samples.

Analysis of indentation creep

2010 ◽  
Vol 25 (4) ◽  
pp. 611-621 ◽  
Author(s):  
Don S. Stone ◽  
Joseph E. Jakes ◽  
Jonathan Puthoff ◽  
Abdelmageed A. Elmustafa
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Fused Silica ◽  
Indentation Creep ◽  
Modulus Ratio ◽  
Element Analysis ◽  
Wide Range ◽  
Self Similar

Finite element analysis is used to simulate cone indentation creep in materials across a wide range of hardness, strain rate sensitivity, and work-hardening exponent. Modeling reveals that the commonly held assumption of the hardness strain rate sensitivity (mH) equaling the flow stress strain rate sensitivity (mσ) is violated except in low hardness/modulus materials. Another commonly held assumption is that for self-similar indenters the indent area increases in proportion to the (depth)2 during creep. This assumption is also violated. Both violations are readily explained by noting that the proportionality “constants” relating (i) hardness to flow stress and (ii) area to (depth)2 are, in reality, functions of hardness/modulus ratio, which changes during creep. Experiments on silicon, fused silica, bulk metallic glass, and poly methyl methacrylate verify the breakdown of the area-(depth)2 relation, consistent with the theory. A method is provided for estimating area from depth during creep.

Sign in / Sign up

Export Citation Format

Share Document