scholarly journals Development of a Transparent Indenter Measurement System and Indentation Analysis for Material Mechanical Property Evaluation

2005 ◽  
Author(s):  
Bruce S. Kang ◽  
Chuanyu Feng
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Surface Deformation ◽  
Plane Deformation ◽  
Contact Radius ◽  
Spherical Indentation ◽  
Stress Strain ◽  
Out Of Plane ◽  
Transparent Indenter

Since Tabor showed the application of spherical indentation approach to obtain material post-yielding true stress-strain curves, the indentation technique has been investigated to determine mechanical properties besides hardness measurement. Accurate measurement of indentation parameters is critical in the determination of surface mechanical properties using indentation method. In this research, an in-situ optical Transparent Indenter Measurement (TIM) method was developed for material inspection and mechanical property measurement. Using spherical indentation, residual surface deformation after spherical indentations was first investigated on IN783 superalloy samples using phase-shifting Twyman-Green and moire´ interferometry. The elastic-plastic boundary was identified based on the characteristic of the out-of-plane deformation fringe patterns. Then using the measured in-plane deformation, yield strength of the tested material was obtained. Using the TIM system, real-time in-situ measurement of indentation-induced out-of-plane deformation and contact radius were directly measured during an indentation process. Coupled with elastic recovery theories and 2D finite element analyses, a procedure was developed to determine the material stress-strain curve. It is also demonstrated that the TIM method is suitable for debonding inspection of thin film materials.

Measurement of Cement in Situ Stresses and Mechanical Properties Without Cooling or Depressurization

2021 ◽  
Author(s):  
Meng Meng ◽  
Luke Frash ◽  
James Carey ◽  
Wenfeng Li ◽  
Nathan Welch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Axial Stress ◽  
Triaxial Compression ◽  
In Situ Measurement ◽  
Poisson's Ratio ◽  
Ambient Conditions

Abstract Accurate characterization of oilwell cement mechanical properties is a prerequisite for maintaining long-term wellbore integrity. The drawback of the most widely used technique is unable to measure the mechanical property under in situ curing environment. We developed a high pressure and high temperature vessel that can hydrate cement under downhole conditions and directly measure its elastic modulus and Poisson's ratio at any interested time point without cooling or depressurization. The equipment has been validated by using water and a reasonable bulk modulus of 2.37 GPa was captured. Neat Class G cement was hydrated in this equipment for seven days under axial stress of 40 MPa, and an in situ measurement in the elastic range shows elastic modulus of 37.3 GPa and Poisson's ratio of 0.15. After that, the specimen was taken out from the vessel, and setted up in the triaxial compression platform. Under a similar confining pressure condition, elastic modulus was 23.6 GPa and Possion's ratio was 0.26. We also measured the properties of cement with the same batch of the slurry but cured under ambient conditions. The elastic modulus was 1.63 GPa, and Poisson's ratio was 0.085. Therefore, we found that the curing condition is significant to cement mechanical property, and the traditional cooling or depressurization method could provide mechanical properties that were quite different (50% difference) from the in situ measurement.

scholarly journals Effect of Post Processing Heat Treatment Routes on Microstructure and Mechanical Property Evolution of Haynes 282 Ni-Based Superalloy Fabricated with Selective Laser Melting (SLM)

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 629
Author(s):  
Anagh Deshpande ◽  
Subrata Deb Nath ◽  
Sundar Atre ◽  
Keng Hsu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Property ◽  
High Temperature ◽  
Selective Laser Melting ◽  
Laser Melting ◽  
Step Heat Treatment ◽  
Microstructure And Mechanical Property ◽  
In Situ Heat Treatment

Selective laser melting (SLM) is one of the most widely used additive manufacturing technologies. Fabricating nickel-based superalloys with SLM has garnered significant interest from the industry and the research community alike due to the excellent high temperature properties and thermal stability exhibited by the alloys. Haynes-282 alloy, a γ′-phase strengthened Ni-based superalloy, has shown good high temperature mechanical properties comparable to alloys like R-41, Waspaloy, and 263 alloy but with better fabricability. A study and comparison of the effect of different heat-treatment routes on microstructure and mechanical property evolution of Haynes-282 fabricated with SLM is lacking in the literature. Hence, in this manuscript, a thorough investigation of microstructure and mechanical properties after a three-step heat treatment and hot isostatic pressing (HIP) has been conducted. In-situ heat-treatment experiments were conducted in a transmission electron microscopy (TEM) to study γ′ precipitate evolution. γ′ precipitation was found to start at 950 °C during in-situ heat-treatment. Insights from the in-situ heat-treatment were used to decide the aging heat-treatment for the alloy. The three-step heat-treatment was found to increase yield strength (YS) and ultimate tensile strength (UTS). HIP process enabled γ′ precipitation and recrystallization of grains of the as-printed samples in one single step.

Mechanical Properties of Hot-Pressed B4C-TiB2 Composites Synthesized from B4C-TiO2 and B4C-TiC

2021 ◽  
Vol 902 ◽  
pp. 81-86
Author(s):  
Shu Mao Zhao ◽  
Ling Ran Zhao
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Volume Fraction ◽  
Raw Materials ◽  
Ceramic Composites ◽  
In Situ Synthesis ◽  
Second Phase ◽  
Pressing Method ◽  
The One

In this study, B4C-TiB2 ceramic composites were manufactured by hot pressing method. The raw materials for the in-situ synthesis of TiB2 were TiO2 and TiC. After being sintered at 1900°C for 60min under a pressure of 30MPa, compact composites samples with a TiB2 volume fraction range from 0 to 11.05% were prepared. The relative density, fracture toughness and flexural strength of different sample were tested. Microstructures on the fracture surface were studied by SEM. The result shows that B4C-TiB2 ceramic composites sintered from B4C-TiC had a better mechanical property than the one sintered from B4C-TiO2. When the content of TiB2 (reacted from TiC) was 11.05vol.%, the strength and toughness of B4C-TiB2 ceramics can reach 598MPa and 6.45MPa·m1/2. The toughening mechanisms of B4C-TiB2 composites include micro-crack toughening and energy consumption by the pulling out process of second phase.

Preparation and Study of PMMA/TiO2 Nanocomposites

2011 ◽  
Vol 233-235 ◽  
pp. 1830-1833 ◽  
Author(s):  
Yong Chen ◽  
Hui Xu ◽  
Tao Sun
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Thermal Stability ◽  
In Situ Polymerization ◽  
The Matrix ◽  
Thermal Stability Of

The PMMA/TiO2 nanocomposites were prepared by in situ polymerization，the dissolution, thermal stability and the mechanical property of the nanocomposites were studied. The results indicated that nano-TiO2 may be crosslinking points in the matrix and the thermal stability of the nanocomposites became higher. As the content of nano-TiO2 increased, the mechanical properties of the nanocomposites had great changes.

The Application of ISDG Method on the Mechanical Property Measurement of the Welding-Line Material

2007 ◽  
Vol 353-358 ◽  
pp. 2724-2727
Author(s):  
Fei Xu ◽  
Meng Hui Zhu ◽  
Zhong Bin Tang ◽  
Yu Long Li
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Yield Stress ◽  
Small Scale ◽  
Small Specimen ◽  
Stress Strain ◽  
Line Material ◽  
Welding Line ◽  
Property Measurement ◽  
Different Parts

The mechanical properties of various parts of the welding-line material are different, while they play very important role in the welding structures, such as the differences of the melted part and the temperature-affected part. In this paper, a non-contacting laser based technique, ISDG (Interference Strain Displacement Gauge) method, is applied to find out these property differences on very small specimen. The testing is very successful and the whole stress-strain curves in such small scale are obtained on different parts of the welding-line material. The soften phenomena of the temperature-affected part is observed by the comparison of the Young’s modulus and yield stress between the melted part and the temperature-affected part.

Microstructure and Mechanical Properties of ZrB2-Based UHTC via Reactive Hot Pressing

2008 ◽  
Vol 368-372 ◽  
pp. 1737-1739
Author(s):  
Qiang Qu ◽  
Wen Bo Han ◽  
Song He Meng ◽  
Xing Hong Zhang ◽  
Jie Cai Han
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Fracture Toughness ◽  
High Temperature ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Volume Ratio ◽  
Ultra High Temperature Ceramics ◽  
Reactive Hot Pressing

ZrB2-based ultra-high temperature ceramics (UHTCs) were prepared from a mixture powder of Zr/B4C/Si with different ratio via reactive hot pressing. The experimental results showed that the sintering temperature above 1800°C was necessary for enhancing the activity of the powders and thus improving the densification of the product. The sinterability and densification properties of ZrB2-based UHTCs meliorated with the amount of Si increasing. However, many large ZrB2 agglomerates formed when the amount of synthesized SiC in the product reached 25vol%, which led to decrease the mechanical property. The composite had highest mechanical properties when the volume ratio of ZrB2: SiC: ZrC was 73.86:20:6.14, and its flexual strength and the fracture toughness were 645.8MPa and 5.66MPa·m1/2 respectively. The microstructure investigation showed the in-situ formed SiC and ZrC were located in the triple point of ZrB2 grains with a size less than 3μm.

Preparations, Structures, and Properties of Polysiloxane-Silica Composites Prepared from a Variety of Hydrolyzable Precursors

1998 ◽  
Vol 520 ◽  
Author(s):  
J. M. Breiner ◽  
J. E. Mark ◽  
G. Beaucage
Keyword(s):  
Mechanical Properties ◽  
Small Angle ◽  
Stress Strain ◽  
Equilibrium Stress ◽  
Strain Measurements ◽  
X Ray ◽  
X Ray Scattering ◽  
Structures And Properties ◽  
Catalyzed Reactions

ABSTRACTPoly(dimethylsiloxane) (PDMS) networks were prepared by tetrafunctionally endlinking hydroxyl-terminated chains with tetraethoxysilane (TEOS). The resulting networks were filled in-situ by hydrolysis-condensation reactions that were either acid or base catalyzed reactions on some novel precursors. These precursors included star-shaped molecules, rings, linear comb-like chains, and pre-hydrolyzed products of silanes such as TEOS. Both monomethoxy and trimethoxy groups were used as hydrolyzable groups on these molecules. The structures of the resulting composites were examined by small-angle X-ray scattering, and their mechanical properties were determined using equilibrium stress-strain measurements in elongation. Novel precursors with monomethoxy functionalities did not generate stable particulates, but those with trimethoxy functionalities did, with some improvements in mechanical properties. Partially-hydrolyzed TEOS provided the best reinforcement of these PDMS elastomers.

scholarly journals Effect of Strain Rate and Extrinsic Size Effect on Micro-Mechanical Properties of Zr-Based Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1611
Author(s):  
Thamer Tabbakh ◽  
Abdulaziz Kurdi ◽  
Animesh Kumar Basak
Keyword(s):  
Mechanical Properties ◽  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Mechanical Loading ◽  
Shear Bands ◽  
Strength Increase ◽  
Stress Strain ◽  
Pillar Diameter

In this study, the mechanical properties and deformation features of Zr-based bulk metallic glass (BMG) are investigated at micro-scale via in situ micro-pillar compression. Furthermore, the effects of the strain rate and micro-pillar diameter on respective stress–strain curves are investigated. Together with the mechanical properties, such unique in situ micro-pillar compression techniques provide physical status to the micro-pillars, referring to the instances of stress–strain curves. It is noted that the effect of the strain rate on the stress–strain behaviour of the BMG diminishes with increasing micro-pillar diameter. In contrast, yield and ultimate compressive strength increase with increasing micro-pillar diameter, up to 4 µm. The deformation details after compression, as a result of conformed mechanical loading, are analysed by SEM and TEM. As evident from electron microscopy investigation, the plastic deformation is evidenced by the presence of multiple slip/shear bands, acting as load accommodation mechanisms in the course of mechanical loading together and resemble local plastic flow (ductile in nature) between two shear plans.

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