Effect of temperature and strain rate in the strength of tantalum. I. Mechanical properties

1981 ◽  
Vol 13 (2) ◽  
pp. 213-216 ◽  
Author(s):  
V. P. Krashchenko ◽  
V. E. Statsenko
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Effect Of Temperature

scholarly journals Experimental Measurements of Mechanical Properties of PUR Foam Used for Testing Medical Devices and Instruments Depending on Temperature, Density and Strain Rate

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4560 ◽  
Author(s):  
Zdenek Horak ◽  
Karel Dvorak ◽  
Lucie Zarybnicka ◽  
Hana Vojackova ◽  
Jana Dvorakova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Mechanical Testing ◽  
Medical Devices ◽  
Optical Microscope ◽  
Surgical Instruments ◽  
Effect Of Temperature ◽  
Experimental Measurements ◽  
Compression Tests ◽  
Biomedical Material

Rigid polyurethane (PUR) foam is products used as a biomedical material for medical device testing. Thermal stability is a very important parameter for evaluating the feasibility of use for testing surgical instrument load during drilling. This work aimed to perform experimental measurements to determine the dependence of the mechanical properties of a certified PUR on temperature, strain rate and density. Experimental measurements were realised for three types of the PUR samples with different density 10, 25 and 40 pounds per cubic foot. The samples were characterised in terms of their mechanical properties evaluated from tensile and compression tests at temperatures of 25 °C, 90 °C and 155 °C. Furthermore, the structures of the samples were characterised using optical microscope, their thermal properties were characterised by thermogravimetric analysis, and their density and stiffness with the effect of temperature was monitored. The results show that it is optimal not only for mechanical testing but also for testing surgical instruments that generate heat during machining. On the basis of experimental measurements and evaluations of the obtained values, the tested materials are suitable for mechanical testing of medical devices. At the same time, this material is also suitable for testing surgical instruments that generate heat during machining.

Mechanical Properties of ZDTP Tribofilms Measured by Nanoindentation: Strain Rate and Temperature Effects

2008 ◽  
Author(s):  
S. Bec ◽  
K. Demmou ◽  
J.-L. Loubet
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Film Formation ◽  
Point Of View ◽  
Effect Of Temperature ◽  
Zinc Dialkyldithiophosphate ◽  
Wear Rates ◽  
Versus Strain ◽  
Antiwear Action

This study aims to contribute to better understand the antiwear action of zinc dialkyldithiophosphate (ZDTP) additives used in car engine lubrication. The antiwear action of ZDTP is associated to the formation of a protective tribofilm onto the rubbing surface. On a mechanical point of view, the efficiency of ZDTP tribofilms results from equilibrium between film formation and wear rates, associated with appropriate rheological properties. In this work, the mechanical properties of a ZDTP tribofilm have been measured by nanoindentation in different test conditions in order to investigate the effect of temperature and strain rate. A Nanoindenter XP® entirely set into a climatic chamber was used to perform the nanoindentation tests. For all tests, an increase of the elastic modulus was observed from a threshold contact pressure value. This effect is similar to the anvil effect observed on polymers: in confined geometry, the elastic modulus increases versus hydrostatic pressure. For the tribofilm, in the studied range, this effect is enhanced at high temperature and low strain rate. Furthermore, when the temperature increases, a change in the rheological behavior of the tribofilm is observed. Up to about 50°C, the tribofilm exhibits viscoplastic behavior — the hardness increases versus strain rate — and above 50°C, the hardness decreases versus strain rate (“shear thinning-like” behavior).

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