The microstructure, tensile property and wear resistance of 7075 aluminum matrix composite reinforced with TiC particles prepared by in-situ reaction casting were investigated. The effect of TiC reinforcement on wear ...The microstructure, tensile property and wear resistance of 7075 aluminum matrix composite reinforced with TiC particles prepared by in-situ reaction casting were investigated. The effect of TiC reinforcement on wear behavior was analyzed. The wear mechanism was also discussed. A micro-mechanism model of reaction kinetics for synthesis of TiC was acquired. Results show that TiC could increase the tensile and yield strength, but decrease the elongation. Besides, TiC particles improve the property of wear resistance of 7075 aluminum alloy. The wear mechanisms include abrasive wear and adhesive wear in wear test process.展开更多
Plasma cladding process was used to prepare the TiC/Ni composite coating on the mild steel substrates. The TiC particles were synthesized in-situ. Microstructure and properties of the coating were investigated by opti...Plasma cladding process was used to prepare the TiC/Ni composite coating on the mild steel substrates. The TiC particles were synthesized in-situ. Microstructure and properties of the coating were investigated by optical microscopy, X-Ray diffraction, SEM, TEM and microhardness tester. The results show that the interface between the coating and the substrate is metallurgically bonded. The coating was uniform and almost defect-free when [Ti+C] varied from 10% to 20% after ball milling. The microstructure of the coating is mainly composed of -Ni dendrite, interdendritic eutectic ( -Ni austenite, M23C6 and CrB) and TiC particles. Most of the TiC particles are spherical and a small fraction is blocky in size of l^2(im. The TiC particles are smaller at the bottom than near the top of the coating. The coating has a gradient microstructure and a highest hardness of lOOOHyO. 1.展开更多
ZL202 matrix composite reinforced by Al2O3 particles was prepared by combining in-situ reaction and casting techniques. Particles' size in the composites was from 1 to 5 microns in diameter. X-ray diffraction anal...ZL202 matrix composite reinforced by Al2O3 particles was prepared by combining in-situ reaction and casting techniques. Particles' size in the composites was from 1 to 5 microns in diameter. X-ray diffraction analysis verified that the reinforcing particleswere δ-Al2O3 which belong to γ-Al2O3 series. The wetting angle between matrix andreinforcement was less than 90°. Energy spectrum analysis indicated that the reactionin bell cover pressing process took place not so completely as in flouring stir process. When the reaction was finished, the matrix was still ZL202 alloy in both.processes.展开更多
A novel process for synthesizing TiNi and TiNi/TiC particles, called the high-temperature salt-melting method, is discussed in this paper. So far as this method is concerned, the molten salts are a reaction medium tha...A novel process for synthesizing TiNi and TiNi/TiC particles, called the high-temperature salt-melting method, is discussed in this paper. So far as this method is concerned, the molten salts are a reaction medium that does not take part in the chemical reaction but can be easily dissolved by water washing. With this method, TiNi shape memory alloy and TiNi/TiC composite particles were prepared in molten salts at 680-850℃. TiNi particles, ranging from 100 nm to several microns in diameter, are obtained and the reverse martensitic transformation is confirmed in these particles by the differential scanning calorimetry (DSC). The reaction temperature and the holding time have no significant influence on the particle size, morphology or the reverse martensitic transformation characteristics. In the molten salts, the released heat of the chemical reaction causes the local temperature to rise quickly, which is the key to obtaining the desired particulate composite.展开更多
The electroslag remelting (ESR) layer reinforced by TiC particles was obtained by electroslag remelting. The microstructure and wear properties of the ESR layer were studied by means of scanning electron microscopy ...The electroslag remelting (ESR) layer reinforced by TiC particles was obtained by electroslag remelting. The microstructure and wear properties of the ESR layer were studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and wear test. The results indicate that TiC particles are synthesized by self-propagating high-temperature synthesis (SHS) reaction during the electroslag remelting process. The size of TiC particles is in the range of 1-10 μm, and the distribution of TiC particles is uniform, from outside to inside of the ESR layer, and the volume fraction and the size of TiC particles decrease gradually. Molten iron and slag flow into porosity due to the SHS process leading to rapid densification and the elimination of porosity in the ESR layer during the ESR process. TiC particles enhance the wear resistance of the ESR layer, whereas CaF2 can improve the high temperature lubricating property of the ESR layer.展开更多
Mierostrueture of the Fe-based alloy hardfaeing coating reinforced by TiC-VC particles was investigated by means of SEM, TEM, XRD and EPMA. The thermodynamics and effect of elements on the carbides were discussed. The...Mierostrueture of the Fe-based alloy hardfaeing coating reinforced by TiC-VC particles was investigated by means of SEM, TEM, XRD and EPMA. The thermodynamics and effect of elements on the carbides were discussed. The result shows that TiC-VC carbides can be formed during arc welding. Carbides with particle size of 2 ~4μm are uniformly dispersed in the matrix. Evidently the covering components and their amount affect the microstrueture and hardness of the coatings. An excellent microstructure and hardness of hardfacing coating were obtained, while the amount of graphite, FeTi and FeV was controlled within the range of 8%- 10%, 15%- 18% and 8%- 12%, respectively.展开更多
In-situ ZrB2/AZ91D magnesium matrix composite was successfully synthesized with Al/K2ZrF6+NH4BF4 by means of Direct Melt Reaction.The fabricated ZrB2/AZ91D magnesium matrix composite through direct melt mixing method ...In-situ ZrB2/AZ91D magnesium matrix composite was successfully synthesized with Al/K2ZrF6+NH4BF4 by means of Direct Melt Reaction.The fabricated ZrB2/AZ91D magnesium matrix composite through direct melt mixing method was investigated.Results from X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) confirmed the existence of ZrB2 particles in the AZ91D alloy,and most ZrB2 particles were in the size range of just several microns,some even to 100 nm.The cast specimens were studied through corrosion testing and heat treatment.The average grain size of AZ91D decreased markedly from about 250μm to 50μm.In addition,the shape and size of the β-Mg17Al12 phase as well as the morphologies of primary α-Mg in the magnesium matrix composite were greatly changed.The network structure of the β-Mg17Al12 phase was broken into small blocks and the size of α-Mg decreased significantly.展开更多
The carbon steels dispersed with ultrafine TiC particles were fabricated by conventional casting method. The casting process is more economical than other available routes for metal matrix composite production, and th...The carbon steels dispersed with ultrafine TiC particles were fabricated by conventional casting method. The casting process is more economical than other available routes for metal matrix composite production, and the large sized components to be fabricated in short processing time. However, it is extremely difficult to obtain uniform dispersion of ultrafine ceramic particles in liquid metals due to the poor wettability and the specific gravity difference between the ceramic particle and metal matrix. In order to solve these problems, the mechanical milling (MM) and surface-active processes were introduced. As a result, Cu coated ultrafine TiC powders made by MM process using high energy ball milling machine were mixed with Sn powders as a surfactant to get better wettability by lowering the surface tension of carbon steel melt. The microstructural investigations by OM show that ultrafine TiC particles are distributed uniformly in carbon steel matrix. The grain sizes of the cast matrix with ultrafine TiC particles are much smaller than those without ultrafine TiC particles. This is probably due to the fact that TiC particles act as nucleation sites during solidification. The wear resistance of cast carbon steel composites added with MMed TiC/Cu-Sn powders is improved due to grain size refinement.展开更多
In this work, the in-situ TiC panicles reinforced composite coating was prepared by plasma transferred arc process on the surface of Q235 steel. Microstructures, phase composition and wear property of the coating were...In this work, the in-situ TiC panicles reinforced composite coating was prepared by plasma transferred arc process on the surface of Q235 steel. Microstructures, phase composition and wear property of the coating were investigated. The results showed that the composite coating consisted mainly of T-Ni, TiC, Cr23C6, Cr7C3, Ni3Si, CrB, Cr5B3 and FeNi3 phases, and was characterized by fine TiC panicles embedded in Ni matrix. The wear resistance of composite coating was significantly improved compared with that of the steel substrate. The wear volume loss of the substrate was 443 mm3, which was about 9 times as that of in-situ TiC particles reinforced composite coating (49 mm3 ). It is mainly attributed to the presence of chromium carbide particles and in-situ TiC particles and their favorable combination with Ni matrix.展开更多
A Ni-base alloy composite coating reinforced with TiC particles of various shapes and sizes on medium carbon steel substrate was produced by multilayer laser cladding. The chemical compositions, microstructures and su...A Ni-base alloy composite coating reinforced with TiC particles of various shapes and sizes on medium carbon steel substrate was produced by multilayer laser cladding. The chemical compositions, microstructures and surface morphology of the cladded layer were analyzed using energy dispersive X-ray spectroscopy (EDX), scanning electron microscope (SEM), and X-ray diffractometry (XRD). The experimental results showed that an excellent metallurgical bonding between the coating and the substrate was obtained. The microstructure of the coating was mainly composed of γ-Ni dendrites, a small amount of CrB, Ni3B, M23C6 and dispersed TiC particles. Much more and larger TiC particles formed in the overlapping zone, which led to a slightly higher microhardness of this zone. The maximum microhardness of the coating was about HV0.21200. The effects of the laser processing parameters on the microstructures and properties of coating were also investigated.展开更多
An in situ synthesized TiC particle reinforced composite layer on Ti6Al4V were fabricated by laser induced reaction of the pre placed mixed powders of Ti and Cr 3C 2. The microstructure of the composite layer was stro...An in situ synthesized TiC particle reinforced composite layer on Ti6Al4V were fabricated by laser induced reaction of the pre placed mixed powders of Ti and Cr 3C 2. The microstructure of the composite layer was strongly related to the composition of original powders and also the laser processing parameters. Under certain processing parameters, the matrix of the composite layer was transferred from dual α + β to single phase β with increasing Cr 3C 2 content in the original powder mixture. The TiC particles were fine and uniformly dispersed in the matrix. Furthermore, the fine TiC particles show excellent compatibility with the matrix, thus offering good wear performance.展开更多
TiC/ZA43 composites were fabricated by XD TM and stirring casting techniques. The tribology properties of the unreinforced ZA43 alloy and the composites were studied by using a block on ring apparatus. Experimental re...TiC/ZA43 composites were fabricated by XD TM and stirring casting techniques. The tribology properties of the unreinforced ZA43 alloy and the composites were studied by using a block on ring apparatus. Experimental results show that the incorporation of TiC particles improves the microstructure of ZA43 matrix alloy. The coefficient of friction μ and the width of worn groove decrease with the increase of TiC volume fraction φ (TiC). The width of worn groove and μ of the composite during wear testing increase with increasing the applied load. Metallographic examinations reveal that unreinforced ZA43 alloy has deep ploughing grooves with obvious adhesion phenomenon, whereas TiC/ZA43 composites have smooth worn surface. Delamination formation is related to the fatigue cracks and the shear cracks on the surface. [展开更多
TiC reinforced titanium composites has been produced with different Al content and C content by XDTM. The results have shown that TiC particles are of two different morphologies f coarse dendritical primary TiC and sh...TiC reinforced titanium composites has been produced with different Al content and C content by XDTM. The results have shown that TiC particles are of two different morphologies f coarse dendritical primary TiC and short bar-shape eutectic TiC. Al content has great effects on the morphology of TiC. With the increasing of Al content, the morphology of primary TiC changes from coarse developed dendrite into short bar-shape or plate--shape TiC with 35%Al. Meanwhile, the structure of the matrix changes from single Ti to Ti and Ti3Al, and to Ti3Al and TiAl. However, the C content has no influence on the microstructure of matrix. When the C content is less than 1.2%, the dendrite TiC disappears and only short bar-shape or plate-shape TiC exists in the composites. In addition, the effect of he3t treatment on the morphology of TiC has also Studied.展开更多
Addition of reinforcement such as TiC, SiC, Al2O3, TiO2, TiN, etc. to Aluminium matrix for enhancing the mechanical properties has been a well established fact. In-situ method of reinforcement of the Aluminium matrix ...Addition of reinforcement such as TiC, SiC, Al2O3, TiO2, TiN, etc. to Aluminium matrix for enhancing the mechanical properties has been a well established fact. In-situ method of reinforcement of the Aluminium matrix with ceramic phase like Titanium Carbide (TiC) is well preferred over the Ex-situ method. In the present investigation, Al-Cu alloy (series of 2014 Aluminium alloy) was used as matrix and reinforced with TiC using In-situ process. The Metal Matrix Composite (MMC) material, Al-4.5%Cu/10%TiC developed exhibited higher yield strength, ultimate strength and hardness as compared to Al-4.5%Cu alloy. Percentage increase in yield and ultimate tensile strengths were reported to be about 15% and 24% respectively whereas Vickers hardness increased by about 35%. The higher values in hardness indicated that the TiC particles contributed to the increase of hardness of matrix. Fractured surface of the tensile specimen of the composite material indicated presence of dimpled surface, indicating thereby a ductile type of fracture. During the fabrication of composite, reaction products such as Al3Ti, Al2Cu and Al3C4 were identified with various morphologies and sizes in metal matrix.展开更多
An approach named direct reaction synthesis (DRS) has been developed to fabricate particulate composites with an extremely fine reinforcement size. ID situ Al matrix composites were fabri-cated by DRS. Extensive analy...An approach named direct reaction synthesis (DRS) has been developed to fabricate particulate composites with an extremely fine reinforcement size. ID situ Al matrix composites were fabri-cated by DRS. Extensive analysis of the composites microstructure using SEM and TEM identify that the reinforcement formed during the DRS process is Ti carbide (TiC) particle, generally less than 1.0 μm. The reacted, semisolid extruded samples exhibit a homogeneous distribution of fine TiC particles in Al-Cu matrix, Mechanical property evaluation of the composites has revealed a very high tensile strength relative to the matrix alloy. Fractographic analysis indicates ductile failure although the ductility and strength are limited by the presence of coarse titanium aluminides (Al3Ti).展开更多
Ultrahard titanium and vanadium carbides (TiC-VC) particles are combined among ferrotitanium (Fe-Ti), ferrovanadium (Fe-V), graphite, rutile, etc. by means of high temperature arc metallurgic reaction in deposited met...Ultrahard titanium and vanadium carbides (TiC-VC) particles are combined among ferrotitanium (Fe-Ti), ferrovanadium (Fe-V), graphite, rutile, etc. by means of high temperature arc metallurgic reaction in deposited metal. The microstructure, properties and wear mechanism of surfacing metal were systemically studied. The results show carbides particles are embedded in Fe matrix, Microstructure of which is lath martensite. The carbides mixed in the lath martensite provide a combination of good hardness and toughness. The residual austenite transforms to martensite, which is caused by the press stress, strengthens the matrix and releases the stress. The surface layers have high abrasive resistance and cracking resistance. The integration of dispersedly distributed carbides, lath martensite and residual austenite of the surface layer results in satisfactory wear resistance.展开更多
基金Supported by the Fundamental Research Funds for the Central Universities(No.2017XKQY007)
文摘The microstructure, tensile property and wear resistance of 7075 aluminum matrix composite reinforced with TiC particles prepared by in-situ reaction casting were investigated. The effect of TiC reinforcement on wear behavior was analyzed. The wear mechanism was also discussed. A micro-mechanism model of reaction kinetics for synthesis of TiC was acquired. Results show that TiC could increase the tensile and yield strength, but decrease the elongation. Besides, TiC particles improve the property of wear resistance of 7075 aluminum alloy. The wear mechanisms include abrasive wear and adhesive wear in wear test process.
文摘Plasma cladding process was used to prepare the TiC/Ni composite coating on the mild steel substrates. The TiC particles were synthesized in-situ. Microstructure and properties of the coating were investigated by optical microscopy, X-Ray diffraction, SEM, TEM and microhardness tester. The results show that the interface between the coating and the substrate is metallurgically bonded. The coating was uniform and almost defect-free when [Ti+C] varied from 10% to 20% after ball milling. The microstructure of the coating is mainly composed of -Ni dendrite, interdendritic eutectic ( -Ni austenite, M23C6 and CrB) and TiC particles. Most of the TiC particles are spherical and a small fraction is blocky in size of l^2(im. The TiC particles are smaller at the bottom than near the top of the coating. The coating has a gradient microstructure and a highest hardness of lOOOHyO. 1.
文摘ZL202 matrix composite reinforced by Al2O3 particles was prepared by combining in-situ reaction and casting techniques. Particles' size in the composites was from 1 to 5 microns in diameter. X-ray diffraction analysis verified that the reinforcing particleswere δ-Al2O3 which belong to γ-Al2O3 series. The wetting angle between matrix andreinforcement was less than 90°. Energy spectrum analysis indicated that the reactionin bell cover pressing process took place not so completely as in flouring stir process. When the reaction was finished, the matrix was still ZL202 alloy in both.processes.
文摘A novel process for synthesizing TiNi and TiNi/TiC particles, called the high-temperature salt-melting method, is discussed in this paper. So far as this method is concerned, the molten salts are a reaction medium that does not take part in the chemical reaction but can be easily dissolved by water washing. With this method, TiNi shape memory alloy and TiNi/TiC composite particles were prepared in molten salts at 680-850℃. TiNi particles, ranging from 100 nm to several microns in diameter, are obtained and the reverse martensitic transformation is confirmed in these particles by the differential scanning calorimetry (DSC). The reaction temperature and the holding time have no significant influence on the particle size, morphology or the reverse martensitic transformation characteristics. In the molten salts, the released heat of the chemical reaction causes the local temperature to rise quickly, which is the key to obtaining the desired particulate composite.
文摘The electroslag remelting (ESR) layer reinforced by TiC particles was obtained by electroslag remelting. The microstructure and wear properties of the ESR layer were studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and wear test. The results indicate that TiC particles are synthesized by self-propagating high-temperature synthesis (SHS) reaction during the electroslag remelting process. The size of TiC particles is in the range of 1-10 μm, and the distribution of TiC particles is uniform, from outside to inside of the ESR layer, and the volume fraction and the size of TiC particles decrease gradually. Molten iron and slag flow into porosity due to the SHS process leading to rapid densification and the elimination of porosity in the ESR layer during the ESR process. TiC particles enhance the wear resistance of the ESR layer, whereas CaF2 can improve the high temperature lubricating property of the ESR layer.
文摘Mierostrueture of the Fe-based alloy hardfaeing coating reinforced by TiC-VC particles was investigated by means of SEM, TEM, XRD and EPMA. The thermodynamics and effect of elements on the carbides were discussed. The result shows that TiC-VC carbides can be formed during arc welding. Carbides with particle size of 2 ~4μm are uniformly dispersed in the matrix. Evidently the covering components and their amount affect the microstrueture and hardness of the coatings. An excellent microstructure and hardness of hardfacing coating were obtained, while the amount of graphite, FeTi and FeV was controlled within the range of 8%- 10%, 15%- 18% and 8%- 12%, respectively.
基金financially supported by the Specialized Research Fund Project for the Doctoral Program of Higher Education of China (No.20070299004)the Jiangsu Higher Education Institutions Natural Science Foundation Research Program (No.10KJD430003)+2 种基金the Jiangsu University Outstanding Talents Building Project (No.1213000004)the Jiangsu University Undergraduate Practice-Innovation Training Project (No.1201220038)Doctoral Foundation of Jiangsu University (No.1281220014)
文摘In-situ ZrB2/AZ91D magnesium matrix composite was successfully synthesized with Al/K2ZrF6+NH4BF4 by means of Direct Melt Reaction.The fabricated ZrB2/AZ91D magnesium matrix composite through direct melt mixing method was investigated.Results from X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) confirmed the existence of ZrB2 particles in the AZ91D alloy,and most ZrB2 particles were in the size range of just several microns,some even to 100 nm.The cast specimens were studied through corrosion testing and heat treatment.The average grain size of AZ91D decreased markedly from about 250μm to 50μm.In addition,the shape and size of the β-Mg17Al12 phase as well as the morphologies of primary α-Mg in the magnesium matrix composite were greatly changed.The network structure of the β-Mg17Al12 phase was broken into small blocks and the size of α-Mg decreased significantly.
基金supported by the Korea Atomic Energy Research Institute (KAERI) R&D Program
文摘The carbon steels dispersed with ultrafine TiC particles were fabricated by conventional casting method. The casting process is more economical than other available routes for metal matrix composite production, and the large sized components to be fabricated in short processing time. However, it is extremely difficult to obtain uniform dispersion of ultrafine ceramic particles in liquid metals due to the poor wettability and the specific gravity difference between the ceramic particle and metal matrix. In order to solve these problems, the mechanical milling (MM) and surface-active processes were introduced. As a result, Cu coated ultrafine TiC powders made by MM process using high energy ball milling machine were mixed with Sn powders as a surfactant to get better wettability by lowering the surface tension of carbon steel melt. The microstructural investigations by OM show that ultrafine TiC particles are distributed uniformly in carbon steel matrix. The grain sizes of the cast matrix with ultrafine TiC particles are much smaller than those without ultrafine TiC particles. This is probably due to the fact that TiC particles act as nucleation sites during solidification. The wear resistance of cast carbon steel composites added with MMed TiC/Cu-Sn powders is improved due to grain size refinement.
文摘In this work, the in-situ TiC panicles reinforced composite coating was prepared by plasma transferred arc process on the surface of Q235 steel. Microstructures, phase composition and wear property of the coating were investigated. The results showed that the composite coating consisted mainly of T-Ni, TiC, Cr23C6, Cr7C3, Ni3Si, CrB, Cr5B3 and FeNi3 phases, and was characterized by fine TiC panicles embedded in Ni matrix. The wear resistance of composite coating was significantly improved compared with that of the steel substrate. The wear volume loss of the substrate was 443 mm3, which was about 9 times as that of in-situ TiC particles reinforced composite coating (49 mm3 ). It is mainly attributed to the presence of chromium carbide particles and in-situ TiC particles and their favorable combination with Ni matrix.
基金This research was supported by the Natural Science Foundation of Inner Mongolia (No. 200508010704)the Science Foundation of Inner Mongolia University of Technology (No. ZD200521) the Postdoctoral Science Foundation of China.
文摘A Ni-base alloy composite coating reinforced with TiC particles of various shapes and sizes on medium carbon steel substrate was produced by multilayer laser cladding. The chemical compositions, microstructures and surface morphology of the cladded layer were analyzed using energy dispersive X-ray spectroscopy (EDX), scanning electron microscope (SEM), and X-ray diffractometry (XRD). The experimental results showed that an excellent metallurgical bonding between the coating and the substrate was obtained. The microstructure of the coating was mainly composed of γ-Ni dendrites, a small amount of CrB, Ni3B, M23C6 and dispersed TiC particles. Much more and larger TiC particles formed in the overlapping zone, which led to a slightly higher microhardness of this zone. The maximum microhardness of the coating was about HV0.21200. The effects of the laser processing parameters on the microstructures and properties of coating were also investigated.
文摘An in situ synthesized TiC particle reinforced composite layer on Ti6Al4V were fabricated by laser induced reaction of the pre placed mixed powders of Ti and Cr 3C 2. The microstructure of the composite layer was strongly related to the composition of original powders and also the laser processing parameters. Under certain processing parameters, the matrix of the composite layer was transferred from dual α + β to single phase β with increasing Cr 3C 2 content in the original powder mixture. The TiC particles were fine and uniformly dispersed in the matrix. Furthermore, the fine TiC particles show excellent compatibility with the matrix, thus offering good wear performance.
文摘TiC/ZA43 composites were fabricated by XD TM and stirring casting techniques. The tribology properties of the unreinforced ZA43 alloy and the composites were studied by using a block on ring apparatus. Experimental results show that the incorporation of TiC particles improves the microstructure of ZA43 matrix alloy. The coefficient of friction μ and the width of worn groove decrease with the increase of TiC volume fraction φ (TiC). The width of worn groove and μ of the composite during wear testing increase with increasing the applied load. Metallographic examinations reveal that unreinforced ZA43 alloy has deep ploughing grooves with obvious adhesion phenomenon, whereas TiC/ZA43 composites have smooth worn surface. Delamination formation is related to the fatigue cracks and the shear cracks on the surface. [
文摘TiC reinforced titanium composites has been produced with different Al content and C content by XDTM. The results have shown that TiC particles are of two different morphologies f coarse dendritical primary TiC and short bar-shape eutectic TiC. Al content has great effects on the morphology of TiC. With the increasing of Al content, the morphology of primary TiC changes from coarse developed dendrite into short bar-shape or plate--shape TiC with 35%Al. Meanwhile, the structure of the matrix changes from single Ti to Ti and Ti3Al, and to Ti3Al and TiAl. However, the C content has no influence on the microstructure of matrix. When the C content is less than 1.2%, the dendrite TiC disappears and only short bar-shape or plate-shape TiC exists in the composites. In addition, the effect of he3t treatment on the morphology of TiC has also Studied.
文摘Addition of reinforcement such as TiC, SiC, Al2O3, TiO2, TiN, etc. to Aluminium matrix for enhancing the mechanical properties has been a well established fact. In-situ method of reinforcement of the Aluminium matrix with ceramic phase like Titanium Carbide (TiC) is well preferred over the Ex-situ method. In the present investigation, Al-Cu alloy (series of 2014 Aluminium alloy) was used as matrix and reinforced with TiC using In-situ process. The Metal Matrix Composite (MMC) material, Al-4.5%Cu/10%TiC developed exhibited higher yield strength, ultimate strength and hardness as compared to Al-4.5%Cu alloy. Percentage increase in yield and ultimate tensile strengths were reported to be about 15% and 24% respectively whereas Vickers hardness increased by about 35%. The higher values in hardness indicated that the TiC particles contributed to the increase of hardness of matrix. Fractured surface of the tensile specimen of the composite material indicated presence of dimpled surface, indicating thereby a ductile type of fracture. During the fabrication of composite, reaction products such as Al3Ti, Al2Cu and Al3C4 were identified with various morphologies and sizes in metal matrix.
文摘An approach named direct reaction synthesis (DRS) has been developed to fabricate particulate composites with an extremely fine reinforcement size. ID situ Al matrix composites were fabri-cated by DRS. Extensive analysis of the composites microstructure using SEM and TEM identify that the reinforcement formed during the DRS process is Ti carbide (TiC) particle, generally less than 1.0 μm. The reacted, semisolid extruded samples exhibit a homogeneous distribution of fine TiC particles in Al-Cu matrix, Mechanical property evaluation of the composites has revealed a very high tensile strength relative to the matrix alloy. Fractographic analysis indicates ductile failure although the ductility and strength are limited by the presence of coarse titanium aluminides (Al3Ti).
文摘Ultrahard titanium and vanadium carbides (TiC-VC) particles are combined among ferrotitanium (Fe-Ti), ferrovanadium (Fe-V), graphite, rutile, etc. by means of high temperature arc metallurgic reaction in deposited metal. The microstructure, properties and wear mechanism of surfacing metal were systemically studied. The results show carbides particles are embedded in Fe matrix, Microstructure of which is lath martensite. The carbides mixed in the lath martensite provide a combination of good hardness and toughness. The residual austenite transforms to martensite, which is caused by the press stress, strengthens the matrix and releases the stress. The surface layers have high abrasive resistance and cracking resistance. The integration of dispersedly distributed carbides, lath martensite and residual austenite of the surface layer results in satisfactory wear resistance.