1989 Vol. 6, No. 1
MECHANICAL PROPERTIES OF GLASS/KEVLAR-49 HYBRID FIBRE COMPOSITE SANDWICH BEAM UNDER BEND/IMPACT LOAD
1989, 6(1): 1-Ⅰ.
Abstract:
The mechanical behaviours of glass fibre composite(GRP),Kevlar-49 fibre composite(KRP) and their hybrid-sandwich beams under bend/impact load have been studied.The modulus,stren gth characters and fracture features of above structures have been analyzed.It has been showed by the test results that the hybrids can improve the anti-bend properties of KRP while the impact proper ties keep the same. The dynamical bend strength(σa) has been introduced for evaluating the strength properties of composites under impact loading, The properties of GRP,KRP and hybrids in three-point bend have been compared with the test results of charpy impact which is similar to the former in loading way.
The mechanical behaviours of glass fibre composite(GRP),Kevlar-49 fibre composite(KRP) and their hybrid-sandwich beams under bend/impact load have been studied.The modulus,stren gth characters and fracture features of above structures have been analyzed.It has been showed by the test results that the hybrids can improve the anti-bend properties of KRP while the impact proper ties keep the same. The dynamical bend strength(σa) has been introduced for evaluating the strength properties of composites under impact loading, The properties of GRP,KRP and hybrids in three-point bend have been compared with the test results of charpy impact which is similar to the former in loading way.
1989, 6(1): 7-Ⅱ.
Abstract:
The surface frce energy of solids is a characteristic factor which affects the surface properties such as absorption,wetting,adhesion, etc.A direct method for its measurement, however,has not yet been established.In this investigation,we developed a method for measuring the surface free energy and its components of glass fibres,which were untreated or treated with various silane coupling agents,by means of electrobalance,It was based on the measurement of the contact angle of a liquid L1 to a solid S under another Liquid L1 to obtain indirectly the surface free eu}srgy of the solid.It can be seen from the result. that the surface free energy of glass fibers is decreased by being treated with s:ilane coupling agents and is. closely dependent on the structure of silanes.If the silane lxas polar function group, the surface free energy of treated glass fibers is high.If the silage has no polar group,the surface free energy is low.The fibres treated with the silane with double bond has m讨dle surface free energy.
The surface frce energy of solids is a characteristic factor which affects the surface properties such as absorption,wetting,adhesion, etc.A direct method for its measurement, however,has not yet been established.In this investigation,we developed a method for measuring the surface free energy and its components of glass fibres,which were untreated or treated with various silane coupling agents,by means of electrobalance,It was based on the measurement of the contact angle of a liquid L1 to a solid S under another Liquid L1 to obtain indirectly the surface free eu}srgy of the solid.It can be seen from the result. that the surface free energy of glass fibers is decreased by being treated with s:ilane coupling agents and is. closely dependent on the structure of silanes.If the silane lxas polar function group, the surface free energy of treated glass fibers is high.If the silage has no polar group,the surface free energy is low.The fibres treated with the silane with double bond has m讨dle surface free energy.
1989, 6(1): 14-Ⅲ.
Abstract:
In this paper,the bending and impact behaviors of the composites of carbon fiber,glass fiber and C/G hybrid fiber reinforced thermoplastics have b,een studied.Two kinds of matrices used in the composites are respectively polysulfone(PSF) and its blend.In the latter a little of bis(4-(4-ethynylphenoxy) phenyl) sulfone(ESF) is added in order to improve the processing and thermostable properties of PSF.
In this paper,the bending and impact behaviors of the composites of carbon fiber,glass fiber and C/G hybrid fiber reinforced thermoplastics have b,een studied.Two kinds of matrices used in the composites are respectively polysulfone(PSF) and its blend.In the latter a little of bis(4-(4-ethynylphenoxy) phenyl) sulfone(ESF) is added in order to improve the processing and thermostable properties of PSF.
1989, 6(1): 21-Ⅳ.
Abstract:
By investigating the effect of impregnation,resin content,and thickness of glass fibre tapes on the process, the feasibility of making continuous prepreg taps by using 648-BF3MEA system in a method of direct hot-melt coat is discussed、The relevant technological parameters and quality control rneasurements are determined too.
By investigating the effect of impregnation,resin content,and thickness of glass fibre tapes on the process, the feasibility of making continuous prepreg taps by using 648-BF3MEA system in a method of direct hot-melt coat is discussed、The relevant technological parameters and quality control rneasurements are determined too.
1989, 6(1): 26-Ⅴ.
Abstract:
The curing properties of diglycidyl ether of bisphenol-A with curing agen is of amine such as tetraethylene-pentamine(TEPA),2-ethyl-4-methylimidazole(EMI-24) have been extensively studied by means of infrared spectrophotometry(IR),and their degrees of curing were measured at different curing temperatures and with different content of amine.
The curing properties of diglycidyl ether of bisphenol-A with curing agen is of amine such as tetraethylene-pentamine(TEPA),2-ethyl-4-methylimidazole(EMI-24) have been extensively studied by means of infrared spectrophotometry(IR),and their degrees of curing were measured at different curing temperatures and with different content of amine.
1989, 6(1): 32-Ⅵ.
Abstract:
In this paper,the thermal and mechanical prcperties,microscopic morphology and acousltic emission(A,E,)response of the intermingled epoxy resin system modified by CTBN and bisphenol A are investigated with 2-ethyl-4-methylimidaze as curing agent.The intermingled epoxy resin system consrists of bifunctional epoxy resin E-51 and tetrafunctional epoxy resin F-76.
In this paper,the thermal and mechanical prcperties,microscopic morphology and acousltic emission(A,E,)response of the intermingled epoxy resin system modified by CTBN and bisphenol A are investigated with 2-ethyl-4-methylimidaze as curing agent.The intermingled epoxy resin system consrists of bifunctional epoxy resin E-51 and tetrafunctional epoxy resin F-76.
1989, 6(1): 40-Ⅵ.
Abstract:
We used PGC to study CF/EP composite interface chemical reactions. From our experimental results we have confirmed that chemical bonding exists in the interface of composites.The surface groups of carbon fibres can react with the epoxide resin(glycidyl ether of β-naphthol) at the temperature as low as 140℃.Temperature lias an acceleration effect on the reactions, aad the acceloration of temperature is more effective at higher temperature, Vie used the carbon fibres that had been oxidized. in HNO3 for 1 hr to react with the以ycidyl ether of β-naphthol for 5 hours, the reaction content of the CF surface groups was 0.009meq/g, 0.014meq/g, 0.03meq/g at 140℃,160℃ and 180℃ respectively.
We used PGC to study CF/EP composite interface chemical reactions. From our experimental results we have confirmed that chemical bonding exists in the interface of composites.The surface groups of carbon fibres can react with the epoxide resin(glycidyl ether of β-naphthol) at the temperature as low as 140℃.Temperature lias an acceleration effect on the reactions, aad the acceloration of temperature is more effective at higher temperature, Vie used the carbon fibres that had been oxidized. in HNO3 for 1 hr to react with the以ycidyl ether of β-naphthol for 5 hours, the reaction content of the CF surface groups was 0.009meq/g, 0.014meq/g, 0.03meq/g at 140℃,160℃ and 180℃ respectively.
1989, 6(1): 46-Ⅶ.
Abstract:
In this paper,the authors first analysed the necessity of making a study of aon-e,s-be}tos friction materials in China right now and the most important point is to select a suitable reinforcement system, After taking a brief review of foreign country researchers' work,the authors ha ve tested the concerned prop;rtics of a s}rics of non-asbestos friction m aterials w hick used non-asbestos reinforcements such as glass fiber,carbon fiber,organic fiber,Kevlar,steel f fiber and mineral fiber.The testing results have shown that the most suitable non-asbestos reinforcement systems in China in recent years are‘glass fiber with modified matrix,pre-oxidized carbon fiber and hybrid fiber system with silicate fiber.
In this paper,the authors first analysed the necessity of making a study of aon-e,s-be}tos friction materials in China right now and the most important point is to select a suitable reinforcement system, After taking a brief review of foreign country researchers' work,the authors ha ve tested the concerned prop;rtics of a s}rics of non-asbestos friction m aterials w hick used non-asbestos reinforcements such as glass fiber,carbon fiber,organic fiber,Kevlar,steel f fiber and mineral fiber.The testing results have shown that the most suitable non-asbestos reinforcement systems in China in recent years are‘glass fiber with modified matrix,pre-oxidized carbon fiber and hybrid fiber system with silicate fiber.
1989, 6(1): 55-Ⅶ.
Abstract:
The subject of casting metal matrix composites reinforced with particles is a rising field in the area of composite materials.This kind of composites possesses potential appliation prospects.Based on the comment on a series of important problems,this paper presents some opinions about the prohlemg exsisting at the present,the future research tasks and the tendency, such as casting technique,wetting and its improving ways,physical and chewical properties of molten metal,interfacial construction and formation. We think that improving continuously and exploiting all kinds of technological methods,unfolding,search in the depth of basic theory and exploiting new materials are the central tasks in the field of casting particle composite materials in the future.
The subject of casting metal matrix composites reinforced with particles is a rising field in the area of composite materials.This kind of composites possesses potential appliation prospects.Based on the comment on a series of important problems,this paper presents some opinions about the prohlemg exsisting at the present,the future research tasks and the tendency, such as casting technique,wetting and its improving ways,physical and chewical properties of molten metal,interfacial construction and formation. We think that improving continuously and exploiting all kinds of technological methods,unfolding,search in the depth of basic theory and exploiting new materials are the central tasks in the field of casting particle composite materials in the future.
1989, 6(1): 62-Ⅷ.
Abstract:
In this paper,carbon fiber-copper composite was made by employing so-called powder-slurry infiltration followed by hot pressing in flowing hydrogen,The transverse tensile strength of the specimens with different fiber volume fractions and pressed at various temperatures was measured,and the microstructure and the fractography after transverse tensile testing was examined by scanning electron microscopy so as to determine the appropriate hot-pressing parameters and their effect on the composite fabrication.
In this paper,carbon fiber-copper composite was made by employing so-called powder-slurry infiltration followed by hot pressing in flowing hydrogen,The transverse tensile strength of the specimens with different fiber volume fractions and pressed at various temperatures was measured,and the microstructure and the fractography after transverse tensile testing was examined by scanning electron microscopy so as to determine the appropriate hot-pressing parameters and their effect on the composite fabrication.
1989, 6(1): 69-Ⅸ.
Abstract:
In this paper,the relations among the solidified structure,tensile strength and growth rate of castings of Al-33.7% Cu eutectic and Al-25.5%Cu hypereutectic alloys have been investigated by the self-made continuous directional solidification(CDS) equipment.It is shown that the long in situ composite castings with shinig surface, homogeneous composition and structure of Al-Cu eutectic and hyper-eutectic alloys can be produced within a wide range of freezing rate by the CDS technology.
In this paper,the relations among the solidified structure,tensile strength and growth rate of castings of Al-33.7% Cu eutectic and Al-25.5%Cu hypereutectic alloys have been investigated by the self-made continuous directional solidification(CDS) equipment.It is shown that the long in situ composite castings with shinig surface, homogeneous composition and structure of Al-Cu eutectic and hyper-eutectic alloys can be produced within a wide range of freezing rate by the CDS technology.
1989, 6(1): 75-Ⅸ.
Abstract:
The interfacial structure of SiC/Al composite has been analyzed by the use of transmission electron micrcscepe(TEM).The SiC/Al composite speciwens for TEM with high fidelity,may be obtained by ultramicrotomy.The results of the studies show that a reaction region with microvoids exists in SiG/Al composite and that there are dense dislocation tangles in the matrix zone adjacent to the interface.
The interfacial structure of SiC/Al composite has been analyzed by the use of transmission electron micrcscepe(TEM).The SiC/Al composite speciwens for TEM with high fidelity,may be obtained by ultramicrotomy.The results of the studies show that a reaction region with microvoids exists in SiG/Al composite and that there are dense dislocation tangles in the matrix zone adjacent to the interface.
1989, 6(1): 80-Ⅹ.
Abstract:
The tensile and impact fractography of carbon fiber reinforced zinc composite prepared by位eans of vacumn liquid-infiltration were investigated respectively with the aid of scanning electron microscopy.The fracture process of the composite was also studied by kinetic longitudinal, off-axis uniaxial and transverse tests.The results show that its normal fracture has a lot of filaments pulled-out and the matrices cleavaged.Its fracture process is that higher stresses at the tip of cracks initiated in the matrices or at the w eaker interface result in debonding of carbon fiber so that the filaments are broken and pulled out,sim ultaneousely othercracks in the matrices propagate and connect along their cleavage planes,leading to the failure of the composite,The influence factors upon the fracture of the composite,such as interfacial bonding strength,fiber orientation and distribution,have also been discussed in this paper.
The tensile and impact fractography of carbon fiber reinforced zinc composite prepared by位eans of vacumn liquid-infiltration were investigated respectively with the aid of scanning electron microscopy.The fracture process of the composite was also studied by kinetic longitudinal, off-axis uniaxial and transverse tests.The results show that its normal fracture has a lot of filaments pulled-out and the matrices cleavaged.Its fracture process is that higher stresses at the tip of cracks initiated in the matrices or at the w eaker interface result in debonding of carbon fiber so that the filaments are broken and pulled out,sim ultaneousely othercracks in the matrices propagate and connect along their cleavage planes,leading to the failure of the composite,The influence factors upon the fracture of the composite,such as interfacial bonding strength,fiber orientation and distribution,have also been discussed in this paper.
