scholarly journals The Mechanical Response of Pre-Shocked Aluminium Single Crystals

2018 ◽  
Vol 183 ◽  
pp. 02010 ◽  
Author(s):  
Jeremy Millett ◽  
George. Gray ◽  
Glenn Whiteman ◽  
Saryu. Fensin ◽  
Gareth Owen
Keyword(s):  
Single Crystals ◽  
Shock Loading ◽  
Mechanical Response ◽  
Spall Strength ◽  
Significant Degree ◽  
Compression Tests ◽  
Static Compression ◽  
One Dimensional ◽  
Post Shock ◽  
Initial Dislocation Density

The behaviour of metals under mechanical loading, including shock loading conditions is strongly influenced by effects such as impurity levels, grain size, initial dislocation density and texture. The work discussed here is part of a wider study on the effects of orientation of aluminium single crystals to one dimensional shock loading, including the Hugoniot Elastic Limit and spall strength. In this work, specimens with three principle directions (<100>, <110> and <111>) parallel to the loading axis have been shock loaded and recovered under conditions of purely one-dimensional strain, with their post shock response monitored by quasi-static compression tests. Results show that the <100> crystal demonstrates a significant degree of post shock hardening, whilst the <111> crystal shows virtually none, and the <110> intermediate between the two. These results are consistent with the ordering of both the HELs and spall strengths observed in a previous paper, and have been explained in terms of the Schmidt factors.

scholarly journals Variations in Hardness with Position In One Dimensionally Recovered Shock Loaded Metals

2018 ◽  
Vol 183 ◽  
pp. 02013 ◽  
Author(s):  
G. Whiteman ◽  
D.L. Higgins ◽  
B. Pang ◽  
J.C.F. Millett ◽  
Y-L. Chiu ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Shock Loading ◽  
Mechanical Response ◽  
High Strain ◽  
Cold Work ◽  
Constitutive Models ◽  
Target Assembly ◽  
One Dimensional ◽  
The Impact

The microstructural and mechanical response of materials to shock loading is of the utmost importance in the development of constitutive models for high strain-rate applications. However, unlike a purely mechanical response, to ensure that the microstructure has been generated under conditions of pure one dimensional strain, the target assembly requires both a complex array of momentum traps to prevent lateral releases entering the specimen location from the edges and spall plates to prevent tensile interactions (spall) affecting the microstructure. In this paper, we examine these effects by performing microhardness profiles of shock loaded copper and tantalum samples. In general, variations in hardness both parallel and perpendicular to the shock direction were small indicating successful momentum trapping. Variations in hardness at different locations relative to the impact face are discussed in terms of the initial degree of cold work and the ability to generate and move dislocations in the samples.

Study of Mechanical Responses and Thermal Expansion of CNF-modified Polyester Nanocomposites Processed by Different Mixing Systems

2011 ◽  
Vol 1312 ◽  
Author(s):  
Muhammad E. Hossain ◽  
Mohammad K. Hossain ◽  
Mahesh Hosur ◽  
Shaik Jeelani
Keyword(s):  
Thermal Expansion ◽  
Mechanical Response ◽  
Carbon Nanofiber ◽  
Coefficient Of Thermal Expansion ◽  
Fracture Morphology ◽  
Mechanical Analysis ◽  
Mechanical And Thermal Properties ◽  
Compression Tests ◽  
Mechanical Mixing ◽  
Static Compression

ABSTRACTIn this study, different dispersion techniques such as sonication at high frequency, mechanical mixing, and magnetic stirring methods were employed to infuse 0.1 to 0.4 wt.% carbon nanofiber (CNF) into polyester matrix to study the influence of CNF on mechanical and thermal properties of the polyester nanocomposites. Dispersion of CNF studied using scanning electron microscopy (SEM) micrographs revealed excellent dispersion of CNF using sonication when 0.2 wt.% CNF was mixed in polyester resulting in enhanced mechanical response. On the other hand, agglomerations were observed in samples prepared with other mixing methods. Polyester with 0.2 wt.% CNF samples prepared by sonication resulted in 88% and 16% increase in flexural strength and modulus, respectively, over neat samples. Quasi-static compression tests showed similar increasing trend with addition of 0.2 wt.% CNF. Dynamic mechanical analysis (DMA) showed 35% and 5 °C improvement in the storage modulus and glass transition temperature (Tg), respectively, in the 0.2 wt.% loaded samples. Thermal mechanical analysis (TMA) performed on neat and samples with 0.2 wt.% CNF showed lower coefficient of thermal expansion (CTE) in nanophased sample compared to neat. Fracture morphology evaluated using SEM revealed relatively rougher surface in CNF-loaded polyester compared to neat as a result of better interaction between fiber and matrix due to the presence of CNF.

Spall strength and fracture behavior of Ti–10V–2Fe–3Al alloy during one-dimensional shock loading

2018 ◽  
Vol 111 ◽  
pp. 77-84 ◽  
Author(s):  
Yu Ren ◽  
Zhiyong Xue ◽  
Xiaodong Yu ◽  
Chengwen Tan ◽  
Fuchi Wang ◽  
...  
Keyword(s):  
Fracture Behavior ◽  
Shock Loading ◽  
Spall Strength ◽  
One Dimensional

Equation of state and mechanical response of NiTi during one-dimensional shock loading

2006 ◽  
Vol 100 (3) ◽  
pp. 033513 ◽  
Author(s):  
Y. J. E. Meziere ◽  
J. C. F. Millett ◽  
N. K. Bourne
Keyword(s):  
Equation Of State ◽  
Shock Loading ◽  
Mechanical Response ◽  
One Dimensional

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

scholarly journals Room-temperature deformation of single crystals of ZrB2 and TiB2 with the hexagonal AlB2 structure investigated by micropillar compression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhenghao Chen ◽  
Bhaskar Paul ◽  
Sanjib Majumdar ◽  
Norihiko L. Okamoto ◽  
Kyosuke Kishida ◽  
...  
Keyword(s):  
Single Crystals ◽  
Plastic Flow ◽  
Room Temperature ◽  
Resolve Shear Stress ◽  
Temperature Deformation ◽  
Slip Systems ◽  
Compression Tests ◽  
Plastic Deformation Behavior ◽  
Bulk Single Crystals ◽  
Micropillar Compression

AbstractThe plastic deformation behavior of single crystals of two transition-metal diborides, ZrB2 and TiB2 with the AlB2 structure has been investigated at room temperature as a function of crystal orientation and specimen size by micropillar compression tests. Although plastic flow is not observed at all for their bulk single crystals at room temperature, plastic flow is successfully observed at room temperature by the operation of slip on {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 3> in ZrB2 and by the operation of slip on {1$${\bar{1}}$$ 1 ¯ 00}<0001> and {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 0> in TiB2. Critical resolve shear stress values at room temperature are very high, exceeding 1 GPa for all observed slip systems; 3.01 GPa for {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 3> slip in ZrB2 and 1.72 GPa and 5.17 GPa, respectively for {1$${\bar{1}}$$ 1 ¯ 00}<0001> and {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 0> slip in TiB2. The identified operative slip systems and their CRSS values are discussed in comparison with those identified in the corresponding bulk single crystals at high temperatures and those inferred from micro-hardness anisotropy in the early studies.

Unexpected photoluminescence properties from one-dimensional molecular chains

Nanoscale ◽  
2016 ◽  
Vol 8 (3) ◽  
pp. 1456-1461 ◽  
Author(s):  
Ye Yuan ◽  
Mingguang Yao ◽  
Shuanglong Chen ◽  
Shijie Liu ◽  
Xigui Yang ◽  
...  
Keyword(s):  
Single Crystals ◽  
Photoluminescence Properties ◽  
One Dimensional

Unlike bulk iodine, iodine molecular chains formed inside one dimensional (1D) nanochannels of AlPO4-5 (AFI) single crystals show unexpected PL behavior.

scholarly journals Visualization of one-dimensional diffusion and spontaneous segregation of hydrogen in single crystals of VO2

2016 ◽  
Vol 27 (34) ◽  
pp. 345708 ◽  
Author(s):  
T Serkan Kasırga ◽  
Jim M Coy ◽  
Jae H Park ◽  
David H Cobden
Keyword(s):  
Single Crystals ◽  
One Dimensional ◽  
Dimensional Diffusion

Evaluation of Belleville Springs and Damping Through Static Cyclic Loading “Hysteresis” for pVARD Optimization: Part-I

2021 ◽  
Author(s):  
Abdelsalam Abugharara ◽  
Stephen Butt
Keyword(s):  
Data Analysis ◽  
Cyclic Loading ◽  
Dynamic Compression ◽  
Range Data ◽  
Compression Tests ◽  
Rotary Drilling ◽  
Static Compression ◽  
Drilling Performance ◽  
Wide Range ◽  
Compression Hysteresis

Abstract One unconventional application that researchers have been investigating for enhancing drilling performance, has been implemented through improving and stabilizing the most effective downhole drilling parameters including (i) increasing downhole dynamic weight on bit (DDWOB), (ii) stabilizing revolution per minutes (rpm), (iii) minimizing destructive downhole vibrations, among many others. As one portion of a three-part-research that consists of a comprehensive data analysis and evaluation of a static compression hysteresis, dynamic compression hysteresis, and corresponding drilling tests, this research investigates through static cyclic loading “Hysteresis” of individual and combined springs and damping the functionality of the passive Vibration Assisted Rotary Drilling (pVARD) tool that could be utilized towards enhancing the drilling performance. Tests are conducted on the two main pVARD tool sections that include (i) Belleville springs, which represent the elasticity portion and (ii) the damping section, which represents the viscous portion. Firstly, tests were conducted through static cyclic loading “Hysteresis” of (i) a mono elastic, (ii) a mono viscus, and (iii) dual elastic-viscus cyclic loading scenarios for the purpose of further examining pVARD functionality. For performing static compression tests, a calibrated geomechanics loading frame was utilized, and various spring stacking of different durometer damping were tested to seek a wide-range data and to provide a multi-angle analysis. Results involved analyzing loading and displacement relationships of individual and combined springs and damping are presented with detailed report of data analysis, discussion, and conclusions.

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