scholarly journals Mechanical properties of lithic raw materials from Kazakhstan: comparing chert, shale, and porphyry

2021 ◽  
Author(s):  
Abay Namen ◽  
Radu Iovita ◽  
Klaus G. Nickel ◽  
Aristeidis Varis ◽  
Zhaken Taimagambetov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fracture Resistance ◽  
Material Selection ◽  
Raw Materials ◽  
Mineralogical Composition ◽  
Raw Material ◽  
Indentation Fracture ◽  
Material Quality ◽  
Lithic Raw Material

The study of lithic raw material quality has become one of the major interpretive tools to investigate the raw material selection behaviour and its influence to the knapping technology. In order to make objective assessments of raw material quality, their mechanical properties (e.g., fracture resistance, hardness, modulus of elasticity) should be measured. However, such comprehensive investigations are lacking for the Palaeolithic of Kazakhstan. In this work, we investigate geological and archaeological lithic raw material samples of chert, porphyry, and shale collected from the Inner Asian Mountain Corridor (henceforth IAMC). Selected samples of aforementioned rocks were tested by means of Vickers and Knoop indentation methods to determine one aspect of their mechanical properties: their indentation fracture resistance (a value closely related to fracture toughness). These tests were complemented by traditional petrographic studies to characterise the mineralogical composition and evaluate the level of impurities that could have potentially affected the mechanical properties. The results show that materials, such as porphyry, previously thought to be of lower quality due to the anisotropic composition and coarse feldspar and quartz phenocrysts embedded in a silica rich matrix, possess fracture toughness values that can be compared to those of chert. Thus, it appears that different raw materials cannot be distinguished from the point of view of indentation fracture resistance, calling for detailed supplementary analyses of different fracture properties. This work also offers first insight into the quality of archaeological porphyry that was utilised as a primary raw material at various Middle and Upper Palaeolithic sites in the IAMC.

In Situ Preparation and Mechanical Properties of (ZrB2+ZrC)/Zr3[Al(Si)]4C6 Composites

2014 ◽  
Vol 602-603 ◽  
pp. 438-442
Author(s):  
Lei Yu ◽  
Jian Yang ◽  
Tai Qiu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Raw Materials ◽  
Linear Increase ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Uniform Microstructure

Fully dense (ZrB2+ZrC)/Zr3[Al (Si)]4C6 composites with ZrB2 content varying from 0 to 15 vol.% and fixed ZrC content of 10 vol.% were successfully prepared by in situ hot-pressing in Ar atmosphere using ZrH2, Al, Si, C and B4C as raw materials. With the increase of ZrB2 content, both the bending strength and fracture toughness of the composites increase and then decrease. The synergistic action of ZrB2 and ZrC as reinforcements shows significant strengthening and toughing effect to the Zr3[Al (Si)]4C6 matrix. The composite with 10 vol.% ZrB2 shows the optimal mechanical properties: 516 MPa for bending strength and 6.52 MPa·m1/2 for fracture toughness. With the increase of ZrB2 content, the Vickers hardness of the composites shows a near-linear increase from 15.3 GPa to 16.7 GPa. The strengthening and toughening effect can be ascribed to the unique mechanical properties of ZrB2 and ZrC reinforcements, the differences in coefficient of thermal expansion and modulus between them and Zr3[Al (Si)]4C6 matrix, fine grain strengthening and uniform microstructure derived by the in situ synthesis reaction.

Use of Sugarcane Bagasse Ashes as Raw Material in the Replacement of Fluxes for Applications on Porcelain Tile

2016 ◽  
Vol 881 ◽  
pp. 383-386 ◽  
Author(s):  
Raimundo J.S. Paranhos ◽  
Wilson Acchar ◽  
Vamberto Monteiro Silva
Keyword(s):  
Mechanical Properties ◽  
Environmental Impact ◽  
Physical Properties ◽  
Sugarcane Bagasse ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Raw Material ◽  
The Cost ◽  
Potential Use ◽  
Porcelain Tile

This study evaluated the potential use of Sugarcane Bagasse Ashes (SBA) as a flux, replacing phyllite for the production of enamelled porcelain tile. The raw materials of the standard mass components and the SBA residue were characterized by testing by XRF, XRD, AG, DTA and TGA. Test samples were fabricated, assembled in lots of 3 units and sintered at temperatures of 1150 ° C to 1210 ° C. The results of the physical properties, mechanical properties and SEM of the sintered samples, showed that the formulation, G4 - in which applied 10% of SBA replacing phyllite, sintering temperature 1210 ° C showed better performance as the previously mentioned properties due to the formation of mullite crystals, meeting the prerequisites of standards for enamelled porcelain tile, while reducing the environmental impact and the cost of production.

scholarly journals Characterization and Analysis of the Carbonation Process of a Lime Mortar Obtained from Phosphogypsum Waste

2021 ◽  
Vol 18 (12) ◽  
pp. 6664
Author(s):  
María Isabel Romero-Hermida ◽  
Antonio María Borrero-López ◽  
Vicente Flores-Alés ◽  
Francisco Javier Alejandre ◽  
José María Franco ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mineralogical Composition ◽  
Barium Sulphate ◽  
Negative Influence ◽  
Raw Material ◽  
Porous System ◽  
Waste Products ◽  
Liesegang Rings ◽  
Carbonation Process ◽  
Ultrasonic Propagation

This work addresses the reuse of waste products as a raw material for lime putties, which are one of the components of mortar. 1:3 Lime/sand mortars very similar to conventional construction mortars were prepared using a lime putty obtained from the treatment of phosphogypsum with sodium hydroxide. The physical, rheological and mechanical properties of this phosphogypsum-derived mortar have been studied, as well as the mineralogical composition, microstructure by scanning electron microscope (SEM) and curing process by monitoring carbonation and ultrasonic propagation velocity. Considering the negative influence of sulphates on the hardened material, the behaviour of the material after sulphates precipitation by adding barium sulphate was additionally tested. Carbonation progressed from the outside to the inside of the specimen through the porous system by Liesegang rings patterns for mortars with soluble sulphates, while the carbonation with precipitated sulphates was controlled by diffusion-precipitation. Overall, the negative influence of low-sulphate contents on the mechanical properties of mortars was verified. It must be highlighted the importance of their precipitation to obtain adequate performance.

scholarly journals Fabrication of Ti3AlC2/Al2O3 nanocomposite by a novel method

2011 ◽  
Vol 43 (3) ◽  
pp. 289-294 ◽  
Author(s):  
J. Zhu ◽  
L. Ye ◽  
F. Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Hot Pressing ◽  
Reaction Path ◽  
Raw Materials ◽  
High Energy ◽  
Good Combination ◽  
High Energy Milling ◽  
Al2o3 Composite ◽  
Novel Method

A Ti3AlC2/Al2O3 nanocomposite was synthesized using Ti, Al, C and TiO2 as raw materials by a novel combination of high-energy milling and hot pressing. The reaction path of the 3Ti-8C-16Al-9TiO2 mixture of powders was investigated, and the results show that the transitional phases TiC, TixAly and Al2O3 are formed in high-energy milling first, and then TixAly is transformed to the TiAl phase during the hot pressing. Finally, a reaction between TiC and TiAl occurs to produce Ti3AlC2 and the nanosized Ti3AlC2/Al2O3 composite is synthesized. The Ti3AlC2/Al2O3 composite possessed a good combination of mechanical properties with a hardness of 6.0 GPa, a flexural strength of 600 MPa, and a fracture toughness (K1C) of 5.8 MPa?m1/2. The strengthening and toughening mechanisms were also discussed.

scholarly journals Automatic Evaluation of the Mechanical Properties of Steels Maraging using Digital Image Processing Techniques

2020 ◽  
Author(s):  
Angélica Alves Viana ◽  
Savio Lopes Rabelo ◽  
José Daniel de Alencar Santos ◽  
Venceslau Xavier de Lima Filho ◽  
Douglas De Araújo Rodrigues ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Maraging Steel ◽  
Raw Material ◽  
High Fracture Toughness ◽  
Mechanical Resistance ◽  
High Fracture ◽  
Traditional System ◽  
Transformation Methods ◽  
Processing Techniques

Some strategic sectors of the economy require that the raw material of their machines and equipment have mechanical properties that satisfy their use. Maraging steel is a material of great concern since it is necessary to have a high mechanical resistance associated with high fracture toughness. The traditional tests to determine the fracture toughness of this material before use in applications are the Charpy and KIC tests. However, this process is characterized by being exhaustive and requiring specialized and trained professionals. Thus, to reverse this situation, this work proposes a new approach to determine the mechanical properties of maraging steel. For this, initially, the method removes any artifacts present in the image resulting from the mode of acquisition. In sequence, this works tested the method Extended Minimum Transformation (EMT) and mathematical morphology to find these markers of the regions of the dimples. Then, the Adaptive Thresholding, Optimal Global Thresholdusing the Otsu Method and Watershed transformation methods were used to segment the dimples. In the end, the diameter of the dimples and the toughness of the material were calculated. Tests are carried out and compared with the result obtained by specialists using the traditional system to evaluate the proposed approach. The results obtained were satisfactory for the application because the proposed approach presented speed and precision to the conventional methods.

scholarly journals Raw material optimization and stone tool engineering in the Early Stone Age of Olduvai Gorge (Tanzania)

2020 ◽  
Vol 17 (162) ◽  
pp. 20190377 ◽  
Author(s):  
Alastair Key ◽  
Tomos Proffitt ◽  
Ignacio de la Torre
Keyword(s):  
Functional Performance ◽  
Material Selection ◽  
Raw Materials ◽  
Cutting Tools ◽  
Raw Material ◽  
Stone Tool ◽  
Olduvai Gorge ◽  
Stone Age ◽  
Material Optimization ◽  
Early Stone Age

For more than 1.8 million years hominins at Olduvai Gorge were faced with a choice: whether to use lavas, quartzite or chert to produce stone tools. All are available locally and all are suitable for stone tool production. Using controlled cutting tests and fracture mechanics theory we examine raw material selection decisions throughout Olduvai's Early Stone Age. We quantify the force, work and material deformation required by each stone type when cutting, before using these data to compare edge sharpness and durability. Significant differences are identified, confirming performance to depend on raw material choice. When combined with artefact data, we demonstrate that Early Stone Age hominins optimized raw material choices based on functional performance characteristics. Doing so flexibly: choosing raw materials dependent on their sharpness and durability, alongside a tool's loading potential and anticipated use-life. In this way, we demonstrate that early lithic artefacts at Olduvai Gorge were engineered to be functionally optimized cutting tools.

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