K. K. Basha, R. Subramanian, T. Satish Kumar, G. Suganya Priyadharshini
This study investigates the effect of ZrO2 reinforcement (5, 10 and 15) vol.% on the dry sliding wear behaviour of AZ31 Mg alloy composites produced using stir casting. The wear test (pin on disc) was conducted at different loads of (10, 20, 30 and 40) N and sliding velocities of (1, 3 and 5) m/s. The variation in the wear rate and friction co-efficient with the change in the load at a constant sliding distance was determined. Results showed that the composites exhibited a lower wear rate at higher loads and speeds compared to the AZ31 alloy. In particular, AZ31-15 vol.% ZrO2 composite showed the lowest wear rate and friction coefficient. Different wear mechanisms operating during the wear test were investigated using SEM and XRD.
{"title":"DRY SLIDING WEAR BEHAVIOUR OF AZ31/ZrO2 COMPOSITES PRODUCED USING A STIR CASTING PROCESS","authors":"K. K. Basha, R. Subramanian, T. Satish Kumar, G. Suganya Priyadharshini","doi":"10.17222/mit.2022.543","DOIUrl":"https://doi.org/10.17222/mit.2022.543","url":null,"abstract":"This study investigates the effect of ZrO2 reinforcement (5, 10 and 15) vol.% on the dry sliding wear behaviour of AZ31 Mg alloy composites produced using stir casting. The wear test (pin on disc) was conducted at different loads of (10, 20, 30 and 40) N and sliding velocities of (1, 3 and 5) m/s. The variation in the wear rate and friction co-efficient with the change in the load at a constant sliding distance was determined. Results showed that the composites exhibited a lower wear rate at higher loads and speeds compared to the AZ31 alloy. In particular, AZ31-15 vol.% ZrO2 composite showed the lowest wear rate and friction coefficient. Different wear mechanisms operating during the wear test were investigated using SEM and XRD. \u0000 ","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"7 1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82898278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper deals with the development of a medical support model that can be used as a prototype to study the anatomy of the femur and for biomechanical research experimentation related to bone plates. CT scan data of the femur bone are converted into a 3D model using MIMICS software and imported into a finite-element model for analysis. The materials selected for the fabrication of the femur model were PEEK and CF PEEK (infused with chopped carbon fibre). The femur bone model was analysed using ANSYS® WORKBENCH® 2021 R2 with different material properties. By conducting a subsequent FE analysis, the optimal material was finally arrived at. Using 3D-printing technology, the 3D model of the femur was fabricated by using a material spool with better properties suited for the femur bone. The FE results were compared with the experimental results of the fabricated femur model and the results of the CF PEEK bone model closely matched the properties of real human femur, and it can be used as a femur bone substitute for biomechanical investigations of bone plates instead of using a real femur.
{"title":"BIO-PRINTING OF FEMUR MODEL: A BONE SUBSTITUTE FOR BIOMEDICAL RESEARCH","authors":"A. Vasanthanathan, Senthil Maharaj Ramesh Kennedy","doi":"10.17222/mit.2023.831","DOIUrl":"https://doi.org/10.17222/mit.2023.831","url":null,"abstract":"This paper deals with the development of a medical support model that can be used as a prototype to study the anatomy of the femur and for biomechanical research experimentation related to bone plates. CT scan data of the femur bone are converted into a 3D model using MIMICS software and imported into a finite-element model for analysis. The materials selected for the fabrication of the femur model were PEEK and CF PEEK (infused with chopped carbon fibre). The femur bone model was analysed using ANSYS® WORKBENCH® 2021 R2 with different material properties. By conducting a subsequent FE analysis, the optimal material was finally arrived at. Using 3D-printing technology, the 3D model of the femur was fabricated by using a material spool with better properties suited for the femur bone. The FE results were compared with the experimental results of the fabricated femur model and the results of the CF PEEK bone model closely matched the properties of real human femur, and it can be used as a femur bone substitute for biomechanical investigations of bone plates instead of using a real femur.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"18 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78805298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper deals with a failure analysis of WC-Co carbide-based twist drills used for small-scale granite drilling. A bench-top drill was used for this study. The aim of the study was to analyse a simulated in-situ rock-drilling operation normally carried out in mines. After a drilling time of 15 minutes, the drills were examined using scanning electron microscopy. On macroscopic observation, both cutting edges of the drills showed slight signs of abrasion, but these were not significant. The chisel edge was also abraded and showed some macroscopic abrasion marks. The electron micrographs showed various signs of decomposition at the micro and nano levels, including cracks in the WC grains, cavities in the grains, Co-binder erosion and some heavy abrasion marks. In addition, some parts of the carbide grains were covered with a thin layer of rock. The wear analysis is an important approach to understanding exactly the damage behaviour of the tool so that the material composition can be changed to avoid premature tool failure.
{"title":"FAILURE ANALYSIS OF CARBIDE TWIST-DRILL BIT FOR SMALL-SCALE GRANITE DRILLING","authors":"Saurabh Dewangan, J. Burja","doi":"10.17222/mit.2023.702","DOIUrl":"https://doi.org/10.17222/mit.2023.702","url":null,"abstract":"This paper deals with a failure analysis of WC-Co carbide-based twist drills used for small-scale granite drilling. A bench-top drill was used for this study. The aim of the study was to analyse a simulated in-situ rock-drilling operation normally carried out in mines. After a drilling time of 15 minutes, the drills were examined using scanning electron microscopy. On macroscopic observation, both cutting edges of the drills showed slight signs of abrasion, but these were not significant. The chisel edge was also abraded and showed some macroscopic abrasion marks. The electron micrographs showed various signs of decomposition at the micro and nano levels, including cracks in the WC grains, cavities in the grains, Co-binder erosion and some heavy abrasion marks. In addition, some parts of the carbide grains were covered with a thin layer of rock. The wear analysis is an important approach to understanding exactly the damage behaviour of the tool so that the material composition can be changed to avoid premature tool failure.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"T161 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82671335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fengde Liu, Yu Gu, Fan Xu, H. Zhang, Shaowei Xu, Zhihang Yan, Zhifeng Yan, Wen-xian Wang
An ER430LNb ferritic stainless steel wire was used for a gas metal arc welding (GMAW) test. The characteristics of droplet transfer and its corresponding voltage and current waveforms were investigated using a high-speed camera and synchronous acquisition of electrical signals. The weld formation, droplet transfer patterns and corresponding microstructures under different welding parameters were observed, and the effect of the current level on the droplet transfer frequency was discussed. As the results show, there were three typical metal transfer patterns during the GMAW using the ER430LNb ferritic stainless steel wire, namely short circuit transfer, mix transfer and spray transfer. With an increase in the welding current, the weld formation is changing constantly, and the droplet transfer frequency increases exponentially. With the change in the transfer pattern, the columnar ferrite structure of the weld is continuously coarsening. In addition, hardness measurements were taken on joints welded at different welding currents for comparison.
{"title":"STUDY OF DROPLET TRANSFER CHARACTERISTICS AND WELD FORMATION WITH ER430LNb FERRITIC STAINLESS STEEL DURING GAS METAL ARC WELDING","authors":"Fengde Liu, Yu Gu, Fan Xu, H. Zhang, Shaowei Xu, Zhihang Yan, Zhifeng Yan, Wen-xian Wang","doi":"10.17222/mit.2022.697","DOIUrl":"https://doi.org/10.17222/mit.2022.697","url":null,"abstract":"An ER430LNb ferritic stainless steel wire was used for a gas metal arc welding (GMAW) test. The characteristics of droplet transfer and its corresponding voltage and current waveforms were investigated using a high-speed camera and synchronous acquisition of electrical signals. The weld formation, droplet transfer patterns and corresponding microstructures under different welding parameters were observed, and the effect of the current level on the droplet transfer frequency was discussed. As the results show, there were three typical metal transfer patterns during the GMAW using the ER430LNb ferritic stainless steel wire, namely short circuit transfer, mix transfer and spray transfer. With an increase in the welding current, the weld formation is changing constantly, and the droplet transfer frequency increases exponentially. With the change in the transfer pattern, the columnar ferrite structure of the weld is continuously coarsening. In addition, hardness measurements were taken on joints welded at different welding currents for comparison.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"73 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90796229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaoyong Ma, Shuping Chen, L. Chen, Yujie Wang, Shufeng Jin, Yang Yu, Maoyuan Mi, Chaofan Shi, Yagang Shi
Flame-retardant multilayer insulation materials act as effective thermal insulation blankets of cryogenic containers that store flammable and explosive cryogenic liquids. This study used standard static liquid nitrogen boil-off calorimetry to test the insulation performance of eight groups of flame-retardant multilayer insulation materials with different wrapping parameters. The effects of four factors, namely the layer density, seaming process, number of reflector layer, and variable-density multilayer insulation arrangement, on the insulation performance were analysed. Three layer densities were considered: 4.47, 3.08, and 2.50 layers/mm. Two types of seaming processes were discussed: the overlapped and fold-over seaming processes. Three numbers of reflector layers were considered: 60, 70, and 80. Two variable-density multilayer insulation arrangements with similar thicknesses were discussed: 10-10-40 and 20-20-20 layers of reflectors allocated for low-, medium- and high-density segments. The conclusions are as follows: Decreasing the layer density enhances the performance of multilayer insulation; Using the fold-over seaming process results in less heat flux and lower apparent thermal conductivity; An increase in the number of reflector layers weakens radiative heat transfer, resulting in better thermal insulation; Furthermore, for a given wrapping thickness, reducing the number of reflectors appropriately in low- and medium-density segments improves the insulation performance; Optimizing and controlling the layer density of each density segment are also essential for variable-density multilayer insulation effects. This study provides supporting theories and reference data for practical engineering applications.
{"title":"EXPERIMENTAL STUDY ON THE FACTORS AFFECTING THE INSULATION PERFORMANCE OF FLAME-RETARDANT MULTILAYER INSULATION MATERIALS","authors":"Xiaoyong Ma, Shuping Chen, L. Chen, Yujie Wang, Shufeng Jin, Yang Yu, Maoyuan Mi, Chaofan Shi, Yagang Shi","doi":"10.17222/mit.2023.736","DOIUrl":"https://doi.org/10.17222/mit.2023.736","url":null,"abstract":"Flame-retardant multilayer insulation materials act as effective thermal insulation blankets of cryogenic containers that store flammable and explosive cryogenic liquids. This study used standard static liquid nitrogen boil-off calorimetry to test the insulation performance of eight groups of flame-retardant multilayer insulation materials with different wrapping parameters. The effects of four factors, namely the layer density, seaming process, number of reflector layer, and variable-density multilayer insulation arrangement, on the insulation performance were analysed. Three layer densities were considered: 4.47, 3.08, and 2.50 layers/mm. Two types of seaming processes were discussed: the overlapped and fold-over seaming processes. Three numbers of reflector layers were considered: 60, 70, and 80. Two variable-density multilayer insulation arrangements with similar thicknesses were discussed: 10-10-40 and 20-20-20 layers of reflectors allocated for low-, medium- and high-density segments. The conclusions are as follows: Decreasing the layer density enhances the performance of multilayer insulation; Using the fold-over seaming process results in less heat flux and lower apparent thermal conductivity; An increase in the number of reflector layers weakens radiative heat transfer, resulting in better thermal insulation; Furthermore, for a given wrapping thickness, reducing the number of reflectors appropriately in low- and medium-density segments improves the insulation performance; Optimizing and controlling the layer density of each density segment are also essential for variable-density multilayer insulation effects. This study provides supporting theories and reference data for practical engineering applications.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"42 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87555259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Salvetr, A. Gokhman, Č. Donik, Z. Nový, Jabub Kotous, M. Godec
The effect of Cu and Si contents on the evolution of embrittlement during a heat treatment consisting of quenching into an oil bath and tempering in the range 200–500 °C was investigated in medium-carbon steels with 0.48 w/% and 0.57 w/% of C. The results showed that the higher silicon content shifted the tempered martensite embrittlement to higher tempering temperatures. The steels alloyed with Cu had lower notch-toughness values, which worsened with increasing tempering temperature compared to the Cu-free samples. In the investigated tempering temperature range, the following microstructural changes occurred: formation of transition carbides, decomposition of retained austenite, and precipitation of cementite and Cu-particles.
{"title":"EVOLUTION OF MICROSTRUCTURE AND EMBRITTLEMENT DURING THE TEMPERING PROCESS IN SiCrCu MEDIUM-CARBON STEELS","authors":"P. Salvetr, A. Gokhman, Č. Donik, Z. Nový, Jabub Kotous, M. Godec","doi":"10.17222/mit.2023.744","DOIUrl":"https://doi.org/10.17222/mit.2023.744","url":null,"abstract":"The effect of Cu and Si contents on the evolution of embrittlement during a heat treatment consisting of quenching into an oil bath and tempering in the range 200–500 °C was investigated in medium-carbon steels with 0.48 w/% and 0.57 w/% of C. The results showed that the higher silicon content shifted the tempered martensite embrittlement to higher tempering temperatures. The steels alloyed with Cu had lower notch-toughness values, which worsened with increasing tempering temperature compared to the Cu-free samples. In the investigated tempering temperature range, the following microstructural changes occurred: formation of transition carbides, decomposition of retained austenite, and precipitation of cementite and Cu-particles.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"37 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73905851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Passive films formed on a Cu-Ni alloy in various concentrations of alkaline environment were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy and the Mott–Schottky approach. The wide passivation range of the copper-nickel alloy was tested in alkaline solutions of three concentrations. The oxide film on the specimen has a p-type semiconductor property, while the flat band potential (EFB) decreased with increasing solution concentration. The film resistance of the passive films increased with increasing solution concentration. The pAassive films showed a duplex structure, including an inner layer of oxide (Cu2O, NiO) and an outer layer of hydroxide (Cu(OH)2, Ni(OH)2).
{"title":"EFFECT OF ALKALINE SOLUTION CONCENTRATION ON THE PASSIVATION FILM OF Cu-Ni ALLOY","authors":"Yue Li, Shuyan Zhao, Xinyu Zhang, Shuo Zhang, Xiaoliang Wu, N. Wu","doi":"10.17222/mit.2023.782","DOIUrl":"https://doi.org/10.17222/mit.2023.782","url":null,"abstract":"Passive films formed on a Cu-Ni alloy in various concentrations of alkaline environment were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy and the Mott–Schottky approach. The wide passivation range of the copper-nickel alloy was tested in alkaline solutions of three concentrations. The oxide film on the specimen has a p-type semiconductor property, while the flat band potential (EFB) decreased with increasing solution concentration. The film resistance of the passive films increased with increasing solution concentration. The pAassive films showed a duplex structure, including an inner layer of oxide (Cu2O, NiO) and an outer layer of hydroxide (Cu(OH)2, Ni(OH)2).","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90863298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaofeng Huang, Junhui Luo, Pengfei Tang, Cheng Xie, J. Chen
Focusing on the problems of low strength and insufficient water stability of the cold patch mixture for asphalt pavement, a polyether polyurethane prepolymer with high activity was prepared in this experiment, and then the epoxy resin was modified with the prepolymer to prepare a kind of epoxy-resin-mixture pothole-repair material with high strength and high toughness. The content of polyurethane prepolymer was optimized using a low-temperature tensile test and a normal-environment-condition mechanical test, and the mechanical properties and road performance of the PU-modified epoxy-resin mixture were studied with a rutting test, bending test, Cantabro scattering and a splitting test. The results show that PU prepolymer-modified epoxy resin can effectively increase the toughness and strength of the binder, and that the toughness and mechanical properties of 20 phr PU prepolymer are the best. The road performance of the PU-modified epoxy-resin cold patch mixture is excellent. There is little difference between the immersion scattering loss rate and the standard loss rate, and both are less than 4 %, indicating that the mixture has excellent anti-scattering and water-loss performance. It is very suitable as a cold patch material for pavement pits. Due to its comprehensive road performance and reasonable price, the use of the PU-modified epoxy resin binder content of 4 % is recommended.
{"title":"PREPARATION AND STUDY OF A PU-MODIFIED EPOXY RESIN COLD PATCHING MIXTURE","authors":"Xiaofeng Huang, Junhui Luo, Pengfei Tang, Cheng Xie, J. Chen","doi":"10.17222/mit.2023.748","DOIUrl":"https://doi.org/10.17222/mit.2023.748","url":null,"abstract":"Focusing on the problems of low strength and insufficient water stability of the cold patch mixture for asphalt pavement, a polyether polyurethane prepolymer with high activity was prepared in this experiment, and then the epoxy resin was modified with the prepolymer to prepare a kind of epoxy-resin-mixture pothole-repair material with high strength and high toughness. The content of polyurethane prepolymer was optimized using a low-temperature tensile test and a normal-environment-condition mechanical test, and the mechanical properties and road performance of the PU-modified epoxy-resin mixture were studied with a rutting test, bending test, Cantabro scattering and a splitting test. The results show that PU prepolymer-modified epoxy resin can effectively increase the toughness and strength of the binder, and that the toughness and mechanical properties of 20 phr PU prepolymer are the best. The road performance of the PU-modified epoxy-resin cold patch mixture is excellent. There is little difference between the immersion scattering loss rate and the standard loss rate, and both are less than 4 %, indicating that the mixture has excellent anti-scattering and water-loss performance. It is very suitable as a cold patch material for pavement pits. Due to its comprehensive road performance and reasonable price, the use of the PU-modified epoxy resin binder content of 4 % is recommended.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"21 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85963731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Malej, Č. Donik, M. Balažic, Matija Bizjak, M. Kac, M. Godec
Additive manufacturing is a complicated process, including powder preparation and post-processing. The atmosphere during the processing of sensitive alloys like Ti6Al4V is among the most important factors. The N content influences the mechanical properties in a significant way. Therefore, it is essential to understand, recognise, and identify the problems in case of machine malfunction or human error. The influence of a low-quality atmosphere on the microstructure evolution and mechanical properties was investigated during the direct energy deposition of hybrid additive-manufactured Ti6Al4V. The properties of the built parts were characterised by chemical analyses, light and electron microscopy, and mechanical testing. High concentrations of N, which absorbed and dissolved with every deposition layer of the direct-energy-deposition process, promoted the formation of a layer of α-scale on the part’s surface. The presence of α-scale was confirmed by observing the sample surfaces and the lack of fusion pores where a layer of α-scale remained. The α-scale partially or entirely dissolved during the next deposition layer. The morphology of the partially melted, α-scale depended on the size of the deposition and, thus, on the temperature evolution during the direct energy deposition.
{"title":"CHARACTERISATION OF THE MICROSTRUCTURE AND DEFECTS DURING THE DIRECT ENERGY DEPOSITION OF HYBRID Ti6Al4V IN A LOW-QUALITY ATMOSPHERE","authors":"S. Malej, Č. Donik, M. Balažic, Matija Bizjak, M. Kac, M. Godec","doi":"10.17222/mit.2023.837","DOIUrl":"https://doi.org/10.17222/mit.2023.837","url":null,"abstract":"Additive manufacturing is a complicated process, including powder preparation and post-processing. The atmosphere during the processing of sensitive alloys like Ti6Al4V is among the most important factors. The N content influences the mechanical properties in a significant way. Therefore, it is essential to understand, recognise, and identify the problems in case of machine malfunction or human error. The influence of a low-quality atmosphere on the microstructure evolution and mechanical properties was investigated during the direct energy deposition of hybrid additive-manufactured Ti6Al4V. The properties of the built parts were characterised by chemical analyses, light and electron microscopy, and mechanical testing. High concentrations of N, which absorbed and dissolved with every deposition layer of the direct-energy-deposition process, promoted the formation of a layer of α-scale on the part’s surface. The presence of α-scale was confirmed by observing the sample surfaces and the lack of fusion pores where a layer of α-scale remained. The α-scale partially or entirely dissolved during the next deposition layer. The morphology of the partially melted, α-scale depended on the size of the deposition and, thus, on the temperature evolution during the direct energy deposition.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"54 4 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80936332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We propose through this work a correlation method leading to a determination of a semi-empirical relationship between optical and electrical properties in terms of refractive index and dark conductivity of doped silicon nanocrystals based on experimental data published in literature. First, an analytical model relating the conductivity and bandgap of doped silicon nanocrystals was derived. Using an empirical expression relating the refractive index to the bandgap energy, we correlated the electrical and optical parameters of N-type nanocrystalline silicon with a semi-empirical expression. The semi-empirical relationship was found to account correctly for the experimental results and yield a reasonably good agreement in an interval of the bandgap energy variation of N-type silicon nanocrystal films. The values of the fitting parameters were calculated for the N-type silicon nanocrystal films having their bandgap energy between 1. 7 eV and 2.2 eV.
{"title":"CORRELATION BETWEEN ELECTRICAL AND OPTICAL PROPERTIES OF DOPED SILICON NANOCRYSTALS","authors":"","doi":"10.17222/mit.2022.720","DOIUrl":"https://doi.org/10.17222/mit.2022.720","url":null,"abstract":"We propose through this work a correlation method leading to a determination of a semi-empirical relationship between optical and electrical properties in terms of refractive index and dark conductivity of doped silicon nanocrystals based on experimental data published in literature. First, an analytical model relating the conductivity and bandgap of doped silicon nanocrystals was derived. Using an empirical expression relating the refractive index to the bandgap energy, we correlated the electrical and optical parameters of N-type nanocrystalline silicon with a semi-empirical expression. The semi-empirical relationship was found to account correctly for the experimental results and yield a reasonably good agreement in an interval of the bandgap energy variation of N-type silicon nanocrystal films. The values of the fitting parameters were calculated for the N-type silicon nanocrystal films having their bandgap energy between 1. 7 eV and 2.2 eV.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"11 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76888524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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