Pub Date : 2021-06-09DOI: 10.24423/ENGTRANS.1172.20210607
Diego Omar Alias, J. E. Ipiña, C. Berejnoi
The minimum sample size for a good estimation of the parameters in both three-parameter Weibull K Jc distribution (3P-W) and ASTM E1921 methods was analyzed. Additionally, the estimations provided by maximum likelihood (ML) and linear regression (LR) were compared. Fracture toughness sets with different sample sizes were randomly generated following a 3P-W with parameters corresponding to experimental datasets from the Euro round robin fracture toughness test. Then, LR and ML were applied to the sets and the parameters were estimated. Standard deviation (SD) and interquartile range (IQR) were employed to analyze the goodness of fit. The results of this paper were consistent with the necessity of large sample sizes (over 30) to find a representative value of the threshold and shape parameters. However, the scale parameter showed a lower scatter and can be estimated with a smaller sample size (around six samples), as used in the standard ASTM E1921-19 b .
{"title":"Analysis of Estimation of Parameters in 3P-Weibull KJc Distribution: Sample Size Effect","authors":"Diego Omar Alias, J. E. Ipiña, C. Berejnoi","doi":"10.24423/ENGTRANS.1172.20210607","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1172.20210607","url":null,"abstract":"The minimum sample size for a good estimation of the parameters in both three-parameter Weibull K Jc distribution (3P-W) and ASTM E1921 methods was analyzed. Additionally, the estimations provided by maximum likelihood (ML) and linear regression (LR) were compared. Fracture toughness sets with different sample sizes were randomly generated following a 3P-W with parameters corresponding to experimental datasets from the Euro round robin fracture toughness test. Then, LR and ML were applied to the sets and the parameters were estimated. Standard deviation (SD) and interquartile range (IQR) were employed to analyze the goodness of fit. The results of this paper were consistent with the necessity of large sample sizes (over 30) to find a representative value of the threshold and shape parameters. However, the scale parameter showed a lower scatter and can be estimated with a smaller sample size (around six samples), as used in the standard ASTM E1921-19 b .","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49390610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-10DOI: 10.24423/ENGTRANS.1100.20210510
Benjamin Giron-Palomares, A. Hernandez-Guerrero, R. Romero-Méndez, H. Qiang
Unsteady analyses of the flow between two egg-carton corrugated plates were performed. Geometry effects on the flow were as follows: “closed recirculations” shrank downstream the channel and became “open recirculations”. For the 180° egg-carton plates, recirculations were z-symmetric to the channel center. Reynolds number increments favored recirculation growth and flow detachment. Transient development effects were as follows: the steady state was reached faster in waves closer to the channel entrance. As time advanced, spatial flow development advanced toward the channel outlet , and y-concave geometries inhibited fluid detachment and steady state achievement. Consequences of the geometry on theransient development of the flow were as follows: the recirculations appeared at larger times, they were smaller, and became “open recirculations” closer to the channel inlet for the 0° model, and the 0° model flow reached a steady state faster. Finally, no clear evidence of unsteady features called “rolling vortices” was observed. Such unsteady features might be a consequence of small unavoidable experimental uncertainties creating a pulsating flow.
{"title":"Unsteady Flow Patterns between Two Egg-Carton Corrugated Plates","authors":"Benjamin Giron-Palomares, A. Hernandez-Guerrero, R. Romero-Méndez, H. Qiang","doi":"10.24423/ENGTRANS.1100.20210510","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1100.20210510","url":null,"abstract":"Unsteady analyses of the flow between two egg-carton corrugated plates were performed. Geometry effects on the flow were as follows: “closed recirculations” shrank downstream the channel and became “open recirculations”. For the 180° egg-carton plates, recirculations were z-symmetric to the channel center. Reynolds number increments favored recirculation growth and flow detachment. Transient development effects were as follows: the steady state was reached faster in waves closer to the channel entrance. As time advanced, spatial flow development advanced toward the channel outlet , and y-concave geometries inhibited fluid detachment and steady state achievement. Consequences of the geometry on theransient development of the flow were as follows: the recirculations appeared at larger times, they were smaller, and became “open recirculations” closer to the channel inlet for the 0° model, and the 0° model flow reached a steady state faster. Finally, no clear evidence of unsteady features called “rolling vortices” was observed. Such unsteady features might be a consequence of small unavoidable experimental uncertainties creating a pulsating flow.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45816428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-26DOI: 10.24423/ENGTRANS.1242.20210126
A. Mejía, M. Alzate, O. Reyes-Ortiz
Particle size distribution of aggregate in asphalt pavements is used for determining important characteristics like stiffness, durability, fatigue resistance, etc. Unfortunately, measuring this distribution requires a sieving process that cannot be done directly on the already mixed pavement. The use of digital image processing could facilitate this measurement, for which it is important to classify aggregate from asphalt in the image. This classification is difficult even for humans and much more for classical image segmentation algorithms. In this paper, an expert committee approach was used, including classical adaptive Otsu, k-means vector quantization over a set of 8 principal components obtained from 26 features, and a Gaussian mixture model whose parameters are estimated through the expectation-maximization algorithm. A novel cellular automata approach is used to coordinate these expert opinions. Finally, a simple heuristic is used to reduce sub- and over-segmentation. The segmentation results are comparable to those obtained by a human expert, while the sieve size of the segmented images corresponds very well with that obtained from the sieving process, validating the proposed method of segmentation. The results show that with the digital imaging procedure it was possible to detect particles with a size of 100 m with 90% of success with respect to time-consuming manual techniques. In addition, with these results it is possible to establish the homogeneity of the sample and the distribution of the particles within the asphalt mixture.
{"title":"Segmentation of Aggregate and Asphalt in Photographic Images of Pavements","authors":"A. Mejía, M. Alzate, O. Reyes-Ortiz","doi":"10.24423/ENGTRANS.1242.20210126","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1242.20210126","url":null,"abstract":"Particle size distribution of aggregate in asphalt pavements is used for determining important characteristics like stiffness, durability, fatigue resistance, etc. Unfortunately, measuring this distribution requires a sieving process that cannot be done directly on the already mixed pavement. The use of digital image processing could facilitate this measurement, for which it is important to classify aggregate from asphalt in the image. This classification is difficult even for humans and much more for classical image segmentation algorithms. In this paper, an expert committee approach was used, including classical adaptive Otsu, k-means vector quantization over a set of 8 principal components obtained from 26 features, and a Gaussian mixture model whose parameters are estimated through the expectation-maximization algorithm. A novel cellular automata approach is used to coordinate these expert opinions. Finally, a simple heuristic is used to reduce sub- and over-segmentation. The segmentation results are comparable to those obtained by a human expert, while the sieve size of the segmented images corresponds very well with that obtained from the sieving process, validating the proposed method of segmentation. The results show that with the digital imaging procedure it was possible to detect particles with a size of 100 m with 90% of success with respect to time-consuming manual techniques. In addition, with these results it is possible to establish the homogeneity of the sample and the distribution of the particles within the asphalt mixture.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45219087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-26DOI: 10.24423/ENGTRANS.1149.20210126
T. Akano, A. Oyelade
The Timoshenko beam theory caters for transverse shear deformations, which are more pronounced in short beams. Previous works were examined, and Hamilton’s principle was used in deriving the governing equation. This research considers two dimensions (2-D): heat and displacement response. A more comprehensive mathematical expression that incorporates this 2-D model on the vibration of a coupled Timoshenko thermoelastic beam and axial deformation effect is formulated. The significance of this model will be expressed through its finite element method (FEM) formulation. The results compared favourably with those of previous works. It was re-established that the amplitude of deflections, as well as cross-sectional rotations, increases considerably as the aspect ratio of the beam decreases. In this way, for larger aspect ratios, the response of the beam is like the quasi-static heating condition. This is expected since the increase in the aspect ratio of the beam reduces its structural stiffness and consequently its natural frequencies. So, the amplitude and temporal period of its vibrations become greater. The beam under the applied thermal loading experiences thermally-induced vibrations. Also, the dynamic solution is substantially influenced by the coupling between strain and temperature fields. The results also reveal that the aspect ratio of the beam could have a significant impact on the vibratory response of the beam. Specifically, it is proportional to the amplitude and temporal period of the thermally-induced vibrations of the beam.
{"title":"On Computational Solution of the Dynamic and Static Behaviour of a Coupled Thermoelastic Timoshenko Beam","authors":"T. Akano, A. Oyelade","doi":"10.24423/ENGTRANS.1149.20210126","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1149.20210126","url":null,"abstract":"The Timoshenko beam theory caters for transverse shear deformations, which are more pronounced in short beams. Previous works were examined, and Hamilton’s principle was used in deriving the governing equation. This research considers two dimensions (2-D): heat and displacement response. A more comprehensive mathematical expression that incorporates this 2-D model on the vibration of a coupled Timoshenko thermoelastic beam and axial deformation effect is formulated. The significance of this model will be expressed through its finite element method (FEM) formulation. The results compared favourably with those of previous works. It was re-established that the amplitude of deflections, as well as cross-sectional rotations, increases considerably as the aspect ratio of the beam decreases. In this way, for larger aspect ratios, the response of the beam is like the quasi-static heating condition. This is expected since the increase in the aspect ratio of the beam reduces its structural stiffness and consequently its natural frequencies. So, the amplitude and temporal period of its vibrations become greater. The beam under the applied thermal loading experiences thermally-induced vibrations. Also, the dynamic solution is substantially influenced by the coupling between strain and temperature fields. The results also reveal that the aspect ratio of the beam could have a significant impact on the vibratory response of the beam. Specifically, it is proportional to the amplitude and temporal period of the thermally-induced vibrations of the beam.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41890762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-26DOI: 10.24423/ENGTRANS.1165.20210126
Alejandro Ruiz Sánchez, Angie Judith Guevara Muñoz, J. S. Río, José A. Montoya
The main purpose of this study is to compare numerically the torque generated by two runners for a gravitational vortex turbine. One of the runners was an H-Darrieus turbine with the rotational flow into the chamber that helped to decrease its negative torque. The other runner was a standard (straight blade) turbine, which determined the performance in both cases. The study was conducted in ANSYSrCFX, where the model was configured at constant operating conditions in both cases. The standard runner performance was higher (75%) than that of the H-Darrieus runner. The highest torque for the standard and the H-Darrieus runners was 0.76 and 0.16 N·m, respectively. The standard runner had a larger fluid contact area than the H-Darrieus runner, which extracted more energy.
{"title":"Numerical Comparison of Two Runners for Gravitational Vortex Turbine","authors":"Alejandro Ruiz Sánchez, Angie Judith Guevara Muñoz, J. S. Río, José A. Montoya","doi":"10.24423/ENGTRANS.1165.20210126","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1165.20210126","url":null,"abstract":"The main purpose of this study is to compare numerically the torque generated by two runners for a gravitational vortex turbine. One of the runners was an H-Darrieus turbine with the rotational flow into the chamber that helped to decrease its negative torque. The other runner was a standard (straight blade) turbine, which determined the performance in both cases. The study was conducted in ANSYSrCFX, where the model was configured at constant operating conditions in both cases. The standard runner performance was higher (75%) than that of the H-Darrieus runner. The highest torque for the standard and the H-Darrieus runners was 0.76 and 0.16 N·m, respectively. The standard runner had a larger fluid contact area than the H-Darrieus runner, which extracted more energy.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43321471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-25DOI: 10.24423/ENGTRANS.1214.20201125
V. Ri̇zov
The present paper considers the time-dependent fracture in a continuously inhomogeneous viscoelastic cantilever beam with two lengthwise cracks. Time-dependent analytical solutions to the strain energy release rate, which take into account the viscoelastic behaviour of the material, are derived. A rheological model with two springs and two dashpots is used for studying the viscoelastic behaviour of the beam. A stress-strain-time relationship is obtained for the case when the rheological model is loaded by stress that increases linearly with time up to a certain level and then it remains constant. The variation of the strain energy release rate with time is analysed.
{"title":"Analysis of Two Lengthwise Cracks in a Viscoelastic Inhomogeneous Beam Structure","authors":"V. Ri̇zov","doi":"10.24423/ENGTRANS.1214.20201125","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1214.20201125","url":null,"abstract":"The present paper considers the time-dependent fracture in a continuously inhomogeneous viscoelastic cantilever beam with two lengthwise cracks. Time-dependent analytical solutions to the strain energy release rate, which take into account the viscoelastic behaviour of the material, are derived. A rheological model with two springs and two dashpots is used for studying the viscoelastic behaviour of the beam. A stress-strain-time relationship is obtained for the case when the rheological model is loaded by stress that increases linearly with time up to a certain level and then it remains constant. The variation of the strain energy release rate with time is analysed.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41356854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-20DOI: 10.24423/ENGTRANS.1174.20201120
K. Magnucki, J. Lewiński, E. Magnucka-Blandzi
This paper is devoted to simply supported beams with bisymmetrical cross-sections under a generalized load. Based on the Zhuravsky shear stress formula, the shear deformation theory of a planar beam cross-section is formulated. The deflections and the shear stresses of example beams are determined. Moreover, the numerical-FEM computations of these beams are carried out. The results of the research are shown in figures and tables.
{"title":"A Shear Deformation Theory of Beams with Bisymmetrical Cross-Sections Based on the Zhuravsky Shear Stress Formula","authors":"K. Magnucki, J. Lewiński, E. Magnucka-Blandzi","doi":"10.24423/ENGTRANS.1174.20201120","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1174.20201120","url":null,"abstract":"This paper is devoted to simply supported beams with bisymmetrical cross-sections under a generalized load. Based on the Zhuravsky shear stress formula, the shear deformation theory of a planar beam cross-section is formulated. The deflections and the shear stresses of example beams are determined. Moreover, the numerical-FEM computations of these beams are carried out. The results of the research are shown in figures and tables.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48545990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-20DOI: 10.24423/ENGTRANS.1185.20201120
Andrés Ramírez, J. Graciano-Uribe, Diego Hincapie Zuluga, Edwar Torrez Lopez
Solidification cracking is a critical phenomenon, especially in the welding of AA6XXX, due these alloys present a wider freezing temperature range. The amount of liquid at the end of the solidification is a dominant factor in promoting or reducing the number of cracks. This paper proposes to assess the effect of the heat input in controlling the cracking during the spot welding in AA6061-T6. Four deposit conditions, made with GTAW, were assessed, in which the cracking degree was quantified and compared with the resulting microstructure. This work confirms and explains why the heat input governs the constitutional cooling, which simultaneously controls the microsegregation amount. With low heat input, the segregation is interdendritic, and the eutectic liquid gathers within the grains, which reduces the cracking susceptibility. A high heat input promotes the higher accumulation of eutectic liquid at the grain boundaries, facilitating cracks’ formation and growth. A high concentration of eutectic liquid promotes the healing effect, reducing the formation of cracks.
{"title":"Segregation Effect on Solidification Cracking in Spot Welding of the 6XXX Aluminum","authors":"Andrés Ramírez, J. Graciano-Uribe, Diego Hincapie Zuluga, Edwar Torrez Lopez","doi":"10.24423/ENGTRANS.1185.20201120","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1185.20201120","url":null,"abstract":"Solidification cracking is a critical phenomenon, especially in the welding of AA6XXX, due these alloys present a wider freezing temperature range. The amount of liquid at the end of the solidification is a dominant factor in promoting or reducing the number of cracks. This paper proposes to assess the effect of the heat input in controlling the cracking during the spot welding in AA6061-T6. Four deposit conditions, made with GTAW, were assessed, in which the cracking degree was quantified and compared with the resulting microstructure. This work confirms and explains why the heat input governs the constitutional cooling, which simultaneously controls the microsegregation amount. With low heat input, the segregation is interdendritic, and the eutectic liquid gathers within the grains, which reduces the cracking susceptibility. A high heat input promotes the higher accumulation of eutectic liquid at the grain boundaries, facilitating cracks’ formation and growth. A high concentration of eutectic liquid promotes the healing effect, reducing the formation of cracks.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45211893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-20DOI: 10.24423/ENGTRANS.1177.20201120
L. Edomwonyi-Otu
This work is targeted at making available some data to enhance the development of better predictive models for drag reduction (DR) in two-phase flows. Oil-water flows studies were carried out by using a horizontal acrylic pipe (14 mm ID) with tap water and a middle distillate oil the flowing liquids. A hydrolysed polyacrylamide served as the polymer in the water phase. Polyethylene oxide (PEO) with two different molecular weights was equally investigated. At an optimal polymer concentration of 20 ppm, drag was lowered as Reynolds number increased. While drag reduction was effectively described by models, it increased with polymer weight.
{"title":"Pressure Drop Reduction in Fluid Flows with a Polymer Solution","authors":"L. Edomwonyi-Otu","doi":"10.24423/ENGTRANS.1177.20201120","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1177.20201120","url":null,"abstract":"This work is targeted at making available some data to enhance the development of better predictive models for drag reduction (DR) in two-phase flows. Oil-water flows studies were carried out by using a horizontal acrylic pipe (14 mm ID) with tap water and a middle distillate oil the flowing liquids. A hydrolysed polyacrylamide served as the polymer in the water phase. Polyethylene oxide (PEO) with two different molecular weights was equally investigated. At an optimal polymer concentration of 20 ppm, drag was lowered as Reynolds number increased. While drag reduction was effectively described by models, it increased with polymer weight.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46503716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-29DOI: 10.24423/ENGTRANS.1156.20201029
A. Subhi, A. A. Khleif, Qasim Saad Abdulwahid
Hypoeutectic Al-7Si alloys containing various titanium proportions (0.8–1.6%) were produced and analyzed in this work. The wear characteristics of Al-Si alloys were studied under the conditions of dry sliding at various applied loads. Optical microscope (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to depict the microstructure, worn surface and phases, respectively. Phases of α-Al, eutectic and Ti9Al23 were recognized in the Al-Si-Ti alloys matrix. Considerable coarsening took place in α-Al and eutectic silicon in a fully eutectic through solidification. The hardness was increased as the titanium proportion increased. Furthermore, significant changes were found in the wear rate depending on the titanium proportion added and load applied.
{"title":"Microstructural Investigation and Wear Characteristics of Al-Si-Ti Cast Alloys","authors":"A. Subhi, A. A. Khleif, Qasim Saad Abdulwahid","doi":"10.24423/ENGTRANS.1156.20201029","DOIUrl":"https://doi.org/10.24423/ENGTRANS.1156.20201029","url":null,"abstract":"Hypoeutectic Al-7Si alloys containing various titanium proportions (0.8–1.6%) were produced and analyzed in this work. The wear characteristics of Al-Si alloys were studied under the conditions of dry sliding at various applied loads. Optical microscope (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to depict the microstructure, worn surface and phases, respectively. Phases of α-Al, eutectic and Ti9Al23 were recognized in the Al-Si-Ti alloys matrix. Considerable coarsening took place in α-Al and eutectic silicon in a fully eutectic through solidification. The hardness was increased as the titanium proportion increased. Furthermore, significant changes were found in the wear rate depending on the \u0000titanium proportion added and load applied.","PeriodicalId":38552,"journal":{"name":"Engineering Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45796212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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