scholarly journals Enhancement of Mechanical Properties of Pure Aluminium through Contactless Melt Sonicating Treatment

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4479
Author(s):  
Agnieszka Dybalska ◽  
Adrian Caden ◽  
William D. Griffiths ◽  
Zakareya Nashwan ◽  
Valdis Bojarevics ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Pure Aluminium ◽  
Test Results ◽  
Extreme Pressure ◽  
Weibull Analysis ◽  
Mean Values ◽  
Untreated Material ◽  
The Mean ◽  
Pressure Changes

A new contactless ultrasonic sonotrode method was previously designed to provide cavitation conditions inside liquid metal. The oscillation of entrapped gas bubbles followed by their final collapse causes extreme pressure changes leading to de-agglomeration and the dispersion of oxide films. The forced wetting of particle surfaces and degassing are other mechanisms that are considered to be involved. Previous publications showed a significant decrease in grain size using this technique. In this paper, the authors extend this research to strength measurements and demonstrate an improvement in cast quality. Degassing effects are also interpreted to illustrate the main mechanisms involved in alloy strengthening. The mean values and Weibull analysis are presented where appropriate to complete the data. The test results on cast Al demonstrated a maximum of 48% grain refinement, a 28% increase in elongation compared to 16% for untreated material and up to 17% increase in ultimate tensile strength (UTS). Under conditions promoting degassing, the hydrogen content was reduced by 0.1 cm3/100 g.

scholarly journals Fabrication of (SiC-AlN)/ZrB2 Composite with Nano-Micron Hybrid Microstructure via PCS-Derived Ceramics Route

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 334
Author(s):  
Aidong Xia ◽  
Jie Yin ◽  
Xiao Chen ◽  
Zhengren Huang ◽  
Xuejian Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Raw Materials ◽  
Secondary Phase ◽  
Pressing Temperature ◽  
Xrd Pattern ◽  
Mean Grain Size ◽  
The Mean

In this work, a (SiC-AlN)/ZrB2 composite with outstanding mechanical properties was prepared by using polymer-derived ceramics (PDCs) and hot-pressing technique. Flexural strength reached up to 460 ± 41 MPa, while AlN and ZrB2 contents were 10 wt%, and 15 wt%, respectively, under a hot-pressing temperature of 2000 °C. XRD pattern-evidenced SiC generated by pyrolysis of polycarbosilane (PCS) was mainly composed by 2H-SiC and 4H-SiC, both belonging to α-SiC. Micron-level ZrB2 secondary phase was observed inside the (SiC-AlN)/ZrB2 composite, while the mean grain size (MGS) of SiC-AlN matrix was approximately 97 nm. This unique nano-micron hybrid microstructure enhanced the mechanical properties. The present investigation provided a feasible tactic for strengthening ceramics from PDCs raw materials.

Microstructure and Mechanical Performance of AZ31-1.7 Wt.% Si Alloy Processed by Cyclic Channel Die Compression

2010 ◽  
Vol 667-669 ◽  
pp. 457-461
Author(s):  
Wei Guo ◽  
Qu Dong Wang ◽  
Man Ping Liu ◽  
Tao Peng ◽  
Xin Tao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Mechanical Performance ◽  
Chinese Script ◽  
Cast State ◽  
Microstructure And Mechanical Properties ◽  
Mean Grain Size ◽  
The Matrix ◽  
The Mean

Cyclic channel die compression (CCDC) of AZ31-1.7 wt.% Si alloy was performed up to 5 passes at 623 K in order to investigate the microstructure and mechanical properties of compressed alloys. The results show that multi-pass CCDC is very effective to refine the matrix grain and Mg2Si phases. After the alloy is processed for 5 passes, the mean grain size decreases from 300 μm of as-cast to 8 μm. Both dendritic and Chinese script type Mg2Si phases break into small polygonal pieces and distribute uniformly in the matrix. The tensile strength increases prominently from 118 MPa to 216 MPa, whereas the hardness of alloy deformed 5 passes only increase by 8.4% compared with as-cast state.

scholarly journals The Compound Influence of Texture and Microstructure on the Mechanical Properties of Low-C Steel Wires

1991 ◽  
Vol 13 (4) ◽  
pp. 243-260 ◽  
Author(s):  
P. Gangli ◽  
J. A. Szpunar ◽  
Sugondo
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Aspect Ratio ◽  
Yield Strength ◽  
Strain Energy ◽  
Size Parameter ◽  
Wire Axis ◽  
Steel Wires ◽  
The Mean ◽  
Homogeneous Strain

A series of experiments were made determining textural, microstructural, and mechanical properties in cold drawn, and spheroidization heat treated low-C steel wires (AISI-1018 and 1033 grades). It was found that texture exerted a significant influence on the mechanical properties, while microstructure had a comparable influence.Mechanical properties are represented by yield strength (YS), ultimate compressive strength (UCS) and by homogeneous strain energy (EHOM), defined by the integral of stress up to uniform elongation. Textural properties are represented by the Taylor-factor, M, the R-value, and by the maximum of the orientation distribution function (ODFMAX). Micro-structural properties are treated with the help of the aspect ratio parameter (1/√AR), where AR is the grain aspect ratio (length to ellipsoidal width), the grain size parameter (1/√D), and the mean free path between second phase spheroidized cementites √N.For cold drawn steel wires, homogeneous strain energy (EHOM) is well correlated to (1/√AR) and (ODFMAX). Yield strength, on the other hand, appears to be chiefly influenced by the aspect ratio parameter, thus here ODFMAX exerts less influence. The yield strength (YS) of annealed, spheroidization treated low-C wires are equally influenced by the grain size parameter (1/√D), the mean distance between spherulites (√N) and by ODFMAX.The textures of the cold drawn wires could be well described by the 〈110〉 fibre parallel to wire axis, and by the 〈111〉 fibre normal to wire axis. The annealed wires, while also featuring these two fibres, displayed a distinct {111}〈110〉single orientation.

scholarly journals The statistical impact of experimental result scatter of asphalt mixtures on their numerical modelling

2019 ◽  
Vol 262 ◽  
pp. 05014 ◽  
Author(s):  
Cezary Szydłowski ◽  
Jarosław Górski ◽  
Marcin Stienss ◽  
Łukasz Smakosz
Keyword(s):  
Numerical Models ◽  
Asphalt Mixture ◽  
Experimental Result ◽  
Model Parameters ◽  
Test Results ◽  
Mean Values ◽  
Estimated Parameters ◽  
The Mean ◽  
Parameter Values ◽  
Test Outcomes

The paper presents selected test results of asphalt mixture conducted in low temperatures. The obtained parameters are highly diverse. It concerns ultimate breaking loads, stiffness parameters related to Young's modulus but also the fracture course. Statistical analysis upon the results makes it possible to relevantly estimate the material-defining parameter values. Such a random approach leads to the mean values of breaking and fracture-triggering loads, dealing with their dispersion too. The estimated parameters allow to form appropriate numerical models of asphalt mixture specimens. This type of analysis supports the laboratory tests. The paper presents the authors' simplified model considering non-uniform material features. The results reflect the scatter of real laboratory test outcomes. In order to do so an algorithm to calibrate the numerical model parameters was created.

Simulation of Fabrication for Single-Phase Al2O3 Ceramic Tool Materials at Different Fabrication Temperature

2010 ◽  
Vol 150-151 ◽  
pp. 1358-1363
Author(s):  
Bin Fang ◽  
Chuan Zhen Huang ◽  
Chong Hai Xu ◽  
Sheng Sun
Keyword(s):  
Mechanical Properties ◽  
Computer Simulation ◽  
Grain Size ◽  
Monte Carlo ◽  
Single Phase ◽  
Two Dimensional ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Mean Grain Size ◽  
The Mean

The fabrication is a key process for the preparation of ceramic tool materials, which governs the mechanical properties of ceramic tool materials under the condition of the same compositions. A computer simulation coupled with fabrication temperature for the hot-pressing process of single-phase ceramic tool materials has been developed using a two-dimensional hexagon lattice model mapped from the realistic microstructure without considering the presence of pores. The fabrication of single-phase Al2O3 is simulated. The mean grain size of simulated microstructure by Monte Carlo Potts model integrated with fabrication temperature increases with an increase in fabrication temperature, which is consistent with the experiment results.

Preparation and characterization of phenolic foam reinforced with expandable graphite and expanded graphite

2017 ◽  
Vol 54 (3) ◽  
pp. 545-559 ◽  
Author(s):  
Kejing Yu ◽  
Xia Luo ◽  
Menglei Wang ◽  
Kun Qian
Keyword(s):  
Mechanical Properties ◽  
Expanded Graphite ◽  
Expandable Graphite ◽  
Test Results ◽  
Compressive Test ◽  
Compression Performance ◽  
Phenolic Foam ◽  
Mean Diameter ◽  
The Mean

In this paper, two kinds of phenolic foams modified with expandable graphite and expanded graphite were prepared and the effect of particles on the mechanical properties and structure of the foams has been discussed. The mechanical properties, density and morphology of reinforced phenolic foams were studied. The images of scanning electron microscope showed that the size of the modified phenolic foams was smaller and more complete. The mean diameter of the expanded graphite-reinforced phenolic foams was smaller than that of the expandable graphite-reinforced phenolic foams due to the specific surface area of the expanded graphite. The compressive test results showed that the expandable graphite and expanded graphite could enhance the mechanical properties of the foams obviously. And the smaller cell size of the expanded graphite-reinforced foams provided them better mechanical properties. When the addition of the reinforcement reached to 0.8 wt%, the reinforced phenolic foams showed the best compression performance. The compressive strength and modulus with the 0.8 wt% expandable graphite were increased by 70% and 48% and that with the 0.8 wt% expanded graphite were increased by 80% and 69%.

Synthesis and Dispersity of YBCO Powder Produced by Oxalic Acid Precipitation Method

2015 ◽  
Vol 645-646 ◽  
pp. 145-150 ◽  
Author(s):  
Ai Qin Wang ◽  
Hui Hui Han ◽  
Min Li ◽  
Jing Pei Xie ◽  
Qing Jie Wu ◽  
...  
Keyword(s):  
Grain Size ◽  
Oxalic Acid ◽  
Technological Parameter ◽  
Oxalic Acid Solution ◽  
Acid Precipitation ◽  
Precipitation Method ◽  
Test Results ◽  
Ph Values ◽  
Mean Grain Size ◽  
The Mean

The YBCO powder was prepared by oxalic acid precipitation method and consequent annealing. The correlation between pH values of oxalic acid solution and the precipitation percentage of precursors were analysed based on thermodynamics analysis. The differential scanning calorimetryanalysis (DSC) was used to confirm the synthetic technological parameter. The phases of powder in each process were investigated by XRD. The microstructures of each powder were tested by SEM and TEM. The mean grain size was calculated by the scherrer’s equation. The test results indicated that the YBCO powder with high purity, less impurities, smaller particle, but severe agglomeration, was Y123 when annealing at 900°C. However, adding dispersants could effectively solve the severe agglomeration. The size of YBCO particles was nanosized and coincided with the calculation.

Mechanical Properties of Porous Nanophase Materials Measured by Instrumental Indentation

1995 ◽  
Vol 400 ◽  
Author(s):  
H. Van Swygenhoven ◽  
W. Wagner ◽  
J. Löffler
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Annealing Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gas Condensation ◽  
Mean Grain Size ◽  
Nanophase Materials ◽  
The Mean ◽  
Instrumental Indentation

AbstractMechanical properties of nanostructured intermetallic Ni3Al synthesized by the inert-gas condensation technique are studied by means of instrumental indentation using the ICT-CSEMEX indenter. This instrument is a microindenter which continously measures load and displacement. Load-displacement curves are performed as function of grain size, consolidation- and annealing temperature. The mean grain size of the samples are studied by means of x-ray diffraction and small-angle neutron scattering.

scholarly journals Altruistic Behavior and Inter-Personal Trust among Behavioral Sciences and Engineering Students

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Nasrina Siddiqi ◽  
Sneha Mishra ◽  
M. Shafiq
Keyword(s):  
Engineering Students ◽  
Behavioral Science ◽  
Sampling Technique ◽  
Altruistic Behavior ◽  
Science Students ◽  
Test Results ◽  
Behavioral Sciences ◽  
Mean Values ◽  
Personal Trust ◽  
The Mean

The purpose of the present investigation was to compare the levels of Inter-Personal Trust and Altruistic Behavior between Behavioral Sciences and Engineering students. Convenience sampling technique has been used to collect data from 100 college students studying in Jamia Millia Islamia University. Of these 100 students, 50 were from Behavioral Science stream (Sociology, Psychology, Political Science and Social Work) and the other 50 were engineering students. The two groups of students (Engineering and Behavioral Sciences students) were compared on the said variables namely, Inter-Personal Trust and Altruistic Behavior, using independent sample t-test. Results suggest that Students studying Behavioral Sciences and those studying engineering differ significantly in terms of Inter-Personal Trust and Altruistic behavior. Moreover, the mean values indicate that Behavioral science students tend to score higher on Altruism as well as Inter-Personal Trust as compared to engineering students.

Performance and Environmental Impact of Rice Straw Fiber Mulching Films Manufactured with a Warming Agent

2019 ◽  
Vol 62 (2) ◽  
pp. 315-320
Author(s):  
Xianglan Ming ◽  
Haitao Chen ◽  
Dianming Ju
Keyword(s):  
Mechanical Properties ◽  
Titanium Dioxide ◽  
Soil Temperature ◽  
Rice Straw ◽  
Peak Position ◽  
Blank Group ◽  
Mean Values ◽  
Accumulated Temperature ◽  
The Mean ◽  
Grade 3

Abstract. This research evaluates the effects of adding various warming agents to rice straw fiber (RSF) films as sustainable alternatives to polyethylene-based films. The results for the mechanical properties of the RSF films with various warming agents show that the mean values of dry tensile strength and bursting strength of the films significantly differed according to the warming agent; in contrast, the mean wet tensile strengths and tearing strengths were not significantly different. The dry tensile strengths of films containing titanium dioxide were 9.7% and 26.8% higher than those of the films containing talc and kaolin, respectively. Additionally, the bursting strengths of the films containing titanium dioxide, calcium carbonate, and talc were 10.5%, 4.4%, and 15.8% higher, respectively, than those of the films containing kaolin. Thus, titanium dioxide was considered the best of the four warming agents for implementation in these films. The absorption peaks of the films with and without titanium dioxide were similar, with some differences in the peak position and relative intensities by Fourier transform infrared spectroscopy. Soil covering tests were conducted with films containing titanium dioxide (TDF), films with no added titanium dioxide, and a blank group. The degradation rate of the TDF reached grade 3 during the bolting stage of bok choy. At soil depths of 0, 5, and 10 cm, the total accumulated temperature of the TDF group was 11.53%, 7.78%, and 5.38% higher, respectively, than that of the blank group. Both TDF degradation and increased soil temperature improved the crop growth and soil microclimate. These results can serve as a reference to further improve the popularization and application of RSF film. Keywords: Degradable films, Mechanical properties, Rice straw, Soil temperature, Titanium dioxide.

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