The Impact of Heat Input on the Microhardness and the Micro-structure of a Welded Carbon Steel and the Modeling of its Micro-crack | Chapter 2 | Current Approaches in Engineering Research and Technology Vol. 2

 The welding process induces changes in the Heat-Affected Zone (HAZ) owing to thermal effects. This implies alterations in mechanical properties and microstructure based on the magnitude of absorbed heat and cooling time. The analysis presented in this article reveals that the base metal, initially composed of ferrite and pearlite, undergoes a change in grain size after welding. During welding, the heat produced during the process can affect the microhardness and the microstructure of the material. The change in the microstructure and the microhardness can be discovered by carrying out a microhardness test on the welded sample and comparing changes in the three different zones i.e the base, the weld and the Heat affected zone (HAZ), or by carrying out a microstructural examination on the welded sample and see the grain dispersion in relation to their sizes. In this work, the weld quality of manual arc welded samples of low-carbon steel St3sp destined for bridge construction to be used in Cameroon has been investigated. After a chemical analysis of the material, a microhardness test and a microstructural examination were also done. Results show that a composition of pearlite and ferrite was seen with a composition of 20/80 respectively. For weld zone and HAZ it changes due to thermal processes. So the micro-structure analysis shows that the base metal is a ferrite and pearlite having a grain size of 11-12 on a scale corresponding to an average grain diameter ≈of 7 microns. The structure of the weld metal is also made up of ferrite and pearlite with columnar crystals of cast metal. The HAZ is made up of Widmanstätten. The width of the HAZ zone is about 1,5mm in different areas of heat affected zone and is observed fine-grained ferrite-pearlite structure with a high degree of dispersion. A micro-crack was revealed with a length of 1,7 mm in the HAZ of sample number 7 and a 1,2 mm length of micro-crack in the weld zone of this same probe was also revealed. The modeling of the micro-crack shows that the velocity of its propagation in the welded zone is higher as much than that in the heat-affected zone i.e. in the welded zone is estimated at 64.59m/s, while in heat affected zone is 0,354.1 m/s. This means that in the absence of welded and environmental defects, failure of structure will be common in the welded zone.

 

Author(s) Details:- 

 

 Mbelle Samuel Bisong
Department of Mechanical Engineering, College of Technology University of Buea, P.O. Box: 63, Buea, Cameroon and Department of Mechanical Engineering, ENSET Douala, P.O. Box: 1872, Douala, Cameroon.

 

Kevin Tsapi Tchoupou
Department of Mechanical and Industrial Engineering, National Higher Polytechnic Institute, University of Bamenda, P.O Box, 39 Bambili, Cameroon.

 

Valeriy V. Lepov
Larionov Institute of Physical-Technical Problems of the North, FRC YSC SB RAS, 1, Oktyabrskaya, 677007 Yakutsk, Russia.

 

Kisito Pierre
Department of Physics, LMMSP University of Dschang, P.O. Box: BP 96, Dschang, Cameroon.

 

Please see the link here:-  https://doi.org/10.9734/bpi/caert/v2/7425B

Physical Properties of the Pb1-xSnxTe Solid Solutions in the Vicinity of the Topological Phase Transition | Chapter 7 | Current Perspective to Physical Science Research Vol. 6

Semiconductor Pb1-xSnxTe solid solutions (PSTS) are well known as promising materials widely used in the IR electronics, thermoelectricity and other fields of science and technology. Recently, it has been found that these alloys in certain concentration ranges exhibit the properties characteristic of the new quantum objects of solid-state physics – topological crystalline insulators (TCIs), whose unique properties define new possibilities for practical use of these materials in spintronics, quantum computing and thermoelectricity. The fact that in PSTS, the band inversion near some composition xc leads to the emergence of the TCI states stimulates a detailed study of the behavior of the lattice, transport, and thermoelectric properties near xc. The goal of the studies presented here was to reveal effects accompanying the band inversion in PSTS by measuring the x-dependences of the heat capacity Cp, microhardness H, lattice thermal conductivity λ L electrical conductivity σ, charge carrier mobility μ H, the Hall coefficient RH, and the Seebeck coefficient S in the range x = (0.59 – 0.68), near the composition (x ~ 0.62) corresponding to the transition to an inversion  state at room temperature. It was established that the transition to the band inverted state is manifested through the appearance of peaks in the isotherms (T = 77-300 K) of  CP, H, σ, RH , μH, and S at x ~ 0.62. In the λL (X) isotherms, we observed two peaks near x =0.61 and x=0.63 and suggested that one peak corresponded to the band inversion point, and the other peak – to a structural self-organization process in the crystal lattice.

Author(s) Details:

E. I. Rogacheva,
National Technical University, Kharkiv Polytechnic Institute, 2 kyrpychova St., 61002 Kharkiv, Ukraine.

G. O. Nikolaenko,
National Technical University, Kharkiv Polytechnic Institute, 2 kyrpychova St., 61002 Kharkiv, Ukraine.

O. N. Nashchekina,
National Technical University, Kharkiv Polytechnic Institute, 2 kyrpychova St., 61002 Kharkiv, Ukraine.

Please see the link here: https://stm.bookpi.org/CPPSR-V6/article/view/13254

Keywords: Pb1–xSnxTe, topological crystalline insulator, band inversion, heat capacity, microhardness, thermal conductivity, electrical conductivity, hall coefficient, charge carrier mobility, seebeck coefficient, self-organization

A Study on Synthesis of Graphene-Aluminum Composite with Improved Microhardness | Chapter 3 | Current Innovations in Chemical and Materials Sciences Vol. 2

 In this study, we efficiently manufactured a 0.2 burden percent usually metallic-graphene composite by ball grinding it for up to 6 hours. The event of the ball grinding trials ranged from two to six hours. Aluminum-graphene composites' microstructural and spectroscopic corresponding was explored by evaluating their characteristics utilizing XRD, FESEM, TEM, Micro-Raman, and microhardness. It was discovered that the second order disorder peak (2D) raised with grinding time. The molting of the composite's graphene is discussed in the Raman ranges of 2D intensity. The extra graphene, at 0.2% burden percent, is harder than the mineral. At 600 0C, composites were sintered. The improvement of the D peak in the globe-milled samples proved that the stacking of element layers had happened separated. In a TEM test, graphene's sheet-like building was demonstrated. Composite establishment is confirmed by XRD.

Author(s) Details:

Binod Bihari Palei,
CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha-751013, India.

Tapan Dash,
Department of Physics, Centurion University of Technology and Management, Odisha, India.

Susanta Kumar Biswal
Department of Chemistry, Centurion University of Technology and Management, Odisha, India.

Please see the link here: https://stm.bookpi.org/CICMS-V2/article/view/12325

Assessment of Biodegradable Blends of Poly(Vinyl Alcohol) and Chitosan for Food Industry and Biomedical Application | Chapter 04 | Current Topics on Chemistry and Biochemistry Vol. 1

 Due to the presence of two types of reactive primary and secondary hydroxyl groups, chitosan (CS), an amino polysaccharide, is a stiff polymer (-OH). It is also a biodegradable, biocompatible, non-toxic, safe, and antibacterial polymer, making it suitable for use in the food and biomedical industries. As a result, biodegradable films based on poly (vinyl alcohol) (PVA) and chitosan (CS) are being developed for usage in food packaging and biomedical applications. The goal of this research is to create a low-cost biodegradable PVA/CS film using a solution casting process with glutaraldehyde as the cross linking agent. Fourier transform infrared spectroscopy (FTIR) and microhardness techniques were used to investigate the intermolecular interactions between constituents of polymer blends and mechanical properties. The degrading characteristics of PVA/CS films were investigated using composting. PVA and PVA/CS mixes had different absorption bands in their FTIR spectra, showing interactions between the blend's components. The marten hardness (HM) value changed from 83.08 MPa in pure PVA to 142.18 MPa (maximum value) with chitosan component of 40% wt. Chitosan boosted the mechanical stiffness of PVA/CS blends by up to 40%, and the optimal combination for the maximum improvement in mechanical properties was determined. This is because blending causes an intermolecular connection between two polymers, which improves the blends' mechanical strength. As the amount of chitosan in the mix rose, the rate of degradation increased.

Author(S) Details

Shanta Pokhrel
Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal.

Rameshwar Adhikari
Research Centre for Applied Science and Technology (RECAST), Tribhuvan University, Kathmandu, Nepal.

Paras Nath Yadav
Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal.

View Book:- https://stm.bookpi.org/CTCB-V1/article/view/6523

Study about Fabrication and Evaluation of Different Thermal Barrier Coating Systems | Chapter 06 | Research Developments in Science and Technology Vol. 1

 Using vitreous enamelling and atmospheric plasma spraying (APS) processes, a new thermal barrier coating (TBC) system with an 8-YSZ top coat, glass-ceramic bond coat, and nimonic supper alloy substrate was created. The APS process was used to create a conventional TBC system consisting of an 8-YSZ top coat, a NiCoCrAlY bond coat, and a nimonic supper alloy substrate. The purpose of this research was to evaluate the thermal cycle performance of glass-ceramic bonded TBC systems to traditional TBC systems. X-ray diffraction analysis for phase identification, scanning electron microscopy for microstructural inspection, energy dispersive X-ray analysis for elemental composition determination, and a Vickers hardness tester for hardness evaluation were used to evaluate both TBC systems. Both TBC systems were also subjected to heat cycling testing at 1000oC for 250 hours using both air and water quenching methods. When comparing the glass-ceramic bond coated TBC system to the standard TBC system, a more gradual transition in microhardness values was discovered, indicating that the new TBC system will provide more reliable performance. Thermal cycling at 1000oC revealed that both TBC systems were stable under air quenching testing for 250 cycles, however coating spallation was seen in water quenching tests for 150 cycles for both TBC systems. Furthermore, the old TBC system showed considerable oxidative weight gain, whereas the new TBC system did not.

Author(S) Details

Poulomi Mukherjee
Bio-ceramics and Coating Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), Kolkata-700 032, India.

Pallabi Roy
Bio-ceramics and Coating Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), Kolkata-700 032, India and Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, (CSIR-HRDC) Campus, Postal Staff College Area, Sector 19, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh- 201 002, India.

Sumana Ghosh
Bio-ceramics and Coating Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), Kolkata-700 032, India.

View Book:- https://stm.bookpi.org/RDST-V1/article/view/6322

Study on Current State of the Technology of Obtaining and Research of Properties of the Corundum-Graphene Composite | Chapter 8 | Research Trends and Challenges in Physical Science Vol. 2

 The goal of this project is to review papers on a small group of composites, corundum graphene in particular. This composite has been the subject of a lot of research in order to make generalisations and find trends.

Author(S) Details

A. G. Zholnin
General Physics Department of The State University of Land Use Planning in Moscow, Russia.

R. S. Hafizov
The State University of Land Use Planning, SULUP, Kazakova str., 105064, Moscow, Russia.

View Book:- https://stm.bookpi.org/RTCPS-V2/article/view/4494

Influence of Technology of Nanopowder Production on the Microstructure of the Sintered by Spark-Plasma Material | Chapter 11 | Recent Trends in Chemical and Material Sciences Vol. 1

A comparison of the Spark-Plasma Sintering (SPS) results of two types of aluminium oxide nanopowders generated through conductor explosion and plasma synthesis. The qualities of the resulting compacts are notably different in mechanical properties and microstructure when the parameters of both powders are similar (spherical form of the particles, size, phase composition), as well as SPS modes. Technological impurities in powders obtained by different procedures are the cause of discrepancies in the qualities of the resultant compacts. Impurities contained in nanopowder created by electro explosion of conductor were artificially added to powder made by plasma synthesis and not containing these impurities, revealing their effect on the creation of the microstructure and characteristics of the sintered by SPS method sample.

Author (s) Details

Dr. A. G. Zholnin
National Research Nuclear University "MEPhI", 115409 Moscow, Kashirskoye Highway, 31, Russia.

Dr. A. P. Melekhov
National Research Nuclear University "MEPhI", 115409 Moscow, Kashirskoye Highway, 31, Russia.

Dr. R. S. Hafizov
State University of Land Management, 105064 Moscow, Kazakova Street 15, Russia.

S. A. Vakulenko
National Research Nuclear University 'MEPhI', 115409 Moscow, Kashirskoye Highway, 31, Russia.

N. A. Rubinkovskiy
National Research Nuclear University 'MEPhI', 115409 Moscow, Kashirskoye Highway, 31, Russia.

A. V. Samokhin
Federal State Institution of Science Institute of Metallurgy and Materials Science of A.A. Baikov of Academy of Sciences (RAS IMET), Russia.

N. V. Alekseev
Federal State Institution of Science Institute of Metallurgy and Materials Science of A.A. Baikov of Academy of Sciences (RAS IMET), Russia.

E. G. Grigoryev
National Research Nuclear University 'MEPhI', 115409 Moscow, Kashirskoye Highway, 31, Russia.

View Book :- https://stm.bookpi.org/RTCAMS-V1/article/view/2188

Determining the Bulk Modulus and Microhardness of Tetrahedral Semiconductors | Chapter 1 | Newest Updates in Physical Science Research Vol. 9

 A universal empirical formula for determining bulk modulus (B) and microhardness (H) was discovered using electronegativity and main quantum number of II-VI, III-V semiconductors. The following are the values of constant C1, which appears in the formulation of bulk modulus, as well as constants C2 and C3, which appear in the expressions of microhardness and the exponent M. C1,C2, C3, and M have numerical values of 206.6, 8.234, 1.291, -1.10 for II-VI semiconductors and 72.4, 31.87, 7.592, -0.95 for III-V semiconductors. Both electro-negativity and main quantum number can properly describe the chemical bonding behaviour of constituent atoms in these semiconductors. The observed bulk modulus and microhardness values match the stated results quite well. The findings of this study will aid in the creation of new semiconductor materials and the study of their mechanical properties.

Author (s) Details

Sanjay Kumar Gorai
Department of Physics, Tata College Chaibasa, Westsingbhum 833201, Jharkhand, India.

View Book :- https://stm.bookpi.org/NUPSR-V9/article/view/1932

An Investigation on SiC and Al Surface Cladding of Ti-6Al-4V for Improved Wear Properties – The Binary Advantage | Chapter 6 | Current Approaches in Science and Technology Research Vol. 5

 Ti-6Al-4V has a high specific strength, toughness, and corrosion resistance, but it has a high friction coefficient, severe adhesive wear, and fretting wear sensitivity. One of the surface modification techniques used to improve on these flaws is laser surface cladding. Laser cladding makes use of the high power density of a focused laser source to heat and melt the surface of the substrate while injecting alloying elements into the melt pool. The surface cladding of the as-received Ti-6Al-4V alloy was done with different ratios of SiC and Al powders using a 4.4Kw continuous wave Nd-YAG laser processor. The SiC powder can act as reinforcing particles and aids in the construction process. The resulting surface metal matrix composite has improved surface wear properties, while aluminum improves wetting between the metal and the reinforcement SiC phase. However, the success of this is dependent on the careful optimization of the powder ratio, which dictates the resulting phases and microstructural evolutions. SEM (energy dispersive spectroscopy), optical microscopy, and x-ray diffraction analysis of the cladding revealed the formation of intermetallic phases such as AlSiTi2, Ti7Al5Si12, TiSi2, AlSi3Ti2, Al6Ti19, Ti2VAl, AlTi3, AlCTi2, Ti3SiC2 and Ti3SiC2. Ti5Si4, which should improve the surface's microhardness and tribological properties compared to the bulk as-received alloy. The best microhardness was 1169.95 Hv, compared to 323.67 Hv for the as-received, and mass loss under abrasive wear tests was only 40% of the as received. This improvement is also reflected in the morphology of the abraded surfaces. The binary combination of Al and SiC powders suffices for significantly improved Ti-6Al-4V surface properties in carefully optimized proportions and laser conditions. Ti5Si4, which should improve the surface's microhardness and tribological properties compared to the bulk as-received alloy. The best microhardness was 1169.95 Hv, compared to 323.67 Hv for the as-received, and mass loss under abrasive wear tests was only 40% of the as received. This improvement is also reflected in the morphology of the abraded surfaces. The binary combination of Al and SiC powders suffices for significantly improved Ti-6Al-4V surface properties in carefully optimized proportions and laser conditions.

Author (s) Details

U. O. Okoli
The Vaal University of Technology, Department of Metallurgical Engineering, Private Bag X021, Andries Potgieter Blvd, Vanderbijlpark, South Africa.

I. O. Otunniyi
The Vaal University of Technology, Department of Metallurgical Engineering, Private Bag X021, Andries Potgieter Blvd, Vanderbijlpark, South Africa.

I. D. Adebiyi
The Vaal University of Technology, Department of Metallurgical Engineering, Private Bag X021, Andries Potgieter Blvd, Vanderbijlpark, South Africa.

View Book :- https://stm.bookpi.org/CASTR-V5/article/view/1615

On the Vickers Microhardness and Wide-Angle X-Ray Line Width for Characterization of the Oxidative Stability of Poly(ethylene-co-propylene) Pipes: New Perspectives | Chapter 6 | Current Research and Development in Chemistry Vol.3

The purpose of the current study is to evaluate the ageing of poly(ethylene-co-propylene) fittings
produced by several manufacturers. The fittings were aged for varying times as follows: 0, 2, 13, 23,
45, 106, 225 and 391 days at 100°C. In a previous paper, the oxidation induction time (OItime) and
oxidation induction temperature (OItemp) were evaluated with respect to every single step of the
ageing process [1]. Here, the Vickers microhardness and wide-angle X-ray line width were used for
characterization of the oxidative stability of poly(ethylene-co-propylene) pipes. Both the Vickers
microhardness and wide-angle X-ray line width as evaluated from a certain reflex of the diffractogram
generally increase with ageing for most samples. The higher microhardness is most likely related to
higher fragility of the pipes. The increase of the X-ray line width with ageing indirectly proves that
reducing the crystallite size as well as increase of the crystallite defectiveness take place.

Author (s) Details

Anton Atanassov Apostolov
Laboratory on Structure and Properties of Polymers, Faculty of Chemistry and Pharmacy, University of Sofia, Sofia, Bulgaria.

View Book :- http://bp.bookpi.org/index.php/bpi/catalog/book/217