Copper, iron and cobalt based pre-alloyed powders for diamond tools were prepared by ultrahigh pressure water atomization（UPWA） process. Pre-alloyed powders prepared by different processes including UPWA, convention...Copper, iron and cobalt based pre-alloyed powders for diamond tools were prepared by ultrahigh pressure water atomization（UPWA） process. Pre-alloyed powders prepared by different processes including UPWA, conventional water atomization （CWA） and elemental metal mechanical mixing （EMMM） were sintered to segments and then compared in mechanical properties, holding force between matrix and diamond, fracture morphology of blank and sintering diamond section containing matrix. The results showed that the pre-alloyed powder prepared by UPWA exhibits the best mechanical properties including the relative density, the hardness and the bending strength of matrix sinteredsegment. Sintered segments fractography of UPWA pre-alloyed powder indicatesmechanical mosaic strength and chemical bonding force between the pre-alloyed powder and the diamond, leading to the great increase in the holding force between matrix and diamond. The mechanical performance andthe service life of diamond tools were greatly improved by UPWA pre-alloyed powders.展开更多
Fine Ni powder is often added to Co and bronze-based metal binder powders for diamond tool segments.Ni is a lower cost substitute for extra-fine Co powder and increases the toughness of Co-Fe diamond binders at the ex...Fine Ni powder is often added to Co and bronze-based metal binder powders for diamond tool segments.Ni is a lower cost substitute for extra-fine Co powder and increases the toughness of Co-Fe diamond binders at the expense of lower hardness and bend strength.In bronze-based diamond binder segments,Ni increases hardness and yield strength.Several grades of Ni powder are used commercially with both Co and bronze-based diamond binders.This paper compares properties of diamond binders containing carbonyl Ni powders including standard Inco(?) T255,T123 PM and T 110 PM.Binder materials were made by ball milling or dry mixing of the fine carbonyl Ni and Fe powders with either XF Co or air atomized bronze(90/10 Cu/Sn) powders.Co-based powder blends were hot pressed at 20～35 MPa and 700℃to 900℃.Bronze-based powder blends were cold pressed and sintered at 840℃.Apparent density,apparent hardness and bend strength(TRS) were compared for different binder compositions and processing conditions.展开更多
In this paper, diamond crystallization from carbonyl nickel powders-C and carbonyl nickel powders + Fe–C systems are investigated in detail at a pressure of 6.0 GPa and temperatures ranging from 1410°C–to 1435&...In this paper, diamond crystallization from carbonyl nickel powders-C and carbonyl nickel powders + Fe–C systems are investigated in detail at a pressure of 6.0 GPa and temperatures ranging from 1410°C–to 1435°C by temperature gradient growth. The effects of Fe additive on the crystal morphology are discussed in the diamond crystallization process.Furthermore, Fourier infrared measurement results indicate that the spectrum of the diamond obtained from Ni + Fe–C system after annealing treatment is nearly consistent with that of natural diamond crystal. We believe that this study is of benefit to a further understanding of the growth mechanism of natural diamond.展开更多
Diamond polycrystal powder has been produced directly from gas phase in an arc discharge plasma jet system.Acetylene diluted in argon was used as hydrocarbon source gas.The product was the mixture of diamond polycryst...Diamond polycrystal powder has been produced directly from gas phase in an arc discharge plasma jet system.Acetylene diluted in argon was used as hydrocarbon source gas.The product was the mixture of diamond polycrystal powders and soot.The 3C cubic phase diamond which is dominant,and the mixture phases of cubic and 6H hexagonal diamond are identified in the produced diamond polycrystal powders by electron diffraction patterns.展开更多
A numerical investigation was carried out to examine the role of micro-sized diamond powder filler on the on-axis tensile stiffness properties of the standard modulus T300 and the high modulus YS90A woven fabric compo...A numerical investigation was carried out to examine the role of micro-sized diamond powder filler on the on-axis tensile stiffness properties of the standard modulus T300 and the high modulus YS90A woven fabric composite plates by progressive damage modeling. Finite element modeling (FEM) results for the T300 composite with and without diamond powder predicted a specific case of fiber failure in all the plies showing the characteristics of brittle failure. Static tensile tests were carried out on the YS90A composite coupons containing no diamond powder (DP) and filled with 6% and 12% volume fractions of DP. A higher content of diamond powder in the coupons led to agglomeration. This induced stress concentrations and subsequently reduced the mechanical properties. FEM was carried out considering specimens with and without an induced stress concentration geometry in the YS90A coupons filled with DP. The results of the on-axis tensile tests indicated a delamination type of failure in both cases with additional fiber fracture in the Open Hole Tensile (OHT) coupons.展开更多
Nanocrystalline WC-Co composite powder and coated tungsten diamond by using vacuum vapor deposition were consolidated by the spark plasma sintering （SPS） process to prepare diamond-enhanced WC-Co cemented carbide co...Nanocrystalline WC-Co composite powder and coated tungsten diamond by using vacuum vapor deposition were consolidated by the spark plasma sintering （SPS） process to prepare diamond-enhanced WC-Co cemented carbide composite materials. The interface microstructures between coated tungsten diamond and WC-Co cemented carbide matrix were investigated by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDXS）. The results showed that there is a transitional layer between the diamond and the matrix, in which the carbon content is 62.97wt.%, and the content of cobalt in the transitional zone is 6.19wt.%; the content of cobalt in the WC-Co cemented carbide matrix is 6.07wt.%, in which the carbon content is 15.95wt.%, and the content of cobalt on the surface of diamond is 7.30wt.%, in which the carbon content is 80.38wt.%. The transitional zone prevents the carbon atom of the diamond from spreading to the matrix, in which the carbon content does coincide with the theoretical value of the raw nanocomposite powders, and the carbon content forms a graded distribution among the matrix, transitional zone, and the surface of diamond; after the 1280℃ SPS consolidated process the diamond still maintains a very good crystal shape, the coated tungsten on the surface of the diamond improves thermal stability of the diamond and increases the bonding strength of the interface between the diamond and the matrix.展开更多
基金Projects(2010SK3172,2015JC3005)supported by the Key Program of Science and Technology Project of Hunan Province,China
文摘Copper, iron and cobalt based pre-alloyed powders for diamond tools were prepared by ultrahigh pressure water atomization（UPWA） process. Pre-alloyed powders prepared by different processes including UPWA, conventional water atomization （CWA） and elemental metal mechanical mixing （EMMM） were sintered to segments and then compared in mechanical properties, holding force between matrix and diamond, fracture morphology of blank and sintering diamond section containing matrix. The results showed that the pre-alloyed powder prepared by UPWA exhibits the best mechanical properties including the relative density, the hardness and the bending strength of matrix sinteredsegment. Sintered segments fractography of UPWA pre-alloyed powder indicatesmechanical mosaic strength and chemical bonding force between the pre-alloyed powder and the diamond, leading to the great increase in the holding force between matrix and diamond. The mechanical performance andthe service life of diamond tools were greatly improved by UPWA pre-alloyed powders.
文摘Fine Ni powder is often added to Co and bronze-based metal binder powders for diamond tool segments.Ni is a lower cost substitute for extra-fine Co powder and increases the toughness of Co-Fe diamond binders at the expense of lower hardness and bend strength.In bronze-based diamond binder segments,Ni increases hardness and yield strength.Several grades of Ni powder are used commercially with both Co and bronze-based diamond binders.This paper compares properties of diamond binders containing carbonyl Ni powders including standard Inco(?) T255,T123 PM and T 110 PM.Binder materials were made by ball milling or dry mixing of the fine carbonyl Ni and Fe powders with either XF Co or air atomized bronze(90/10 Cu/Sn) powders.Co-based powder blends were hot pressed at 20～35 MPa and 700℃to 900℃.Bronze-based powder blends were cold pressed and sintered at 840℃.Apparent density,apparent hardness and bend strength(TRS) were compared for different binder compositions and processing conditions.
基金supported by the National Natural Science Foundation of China(Grant No.51172089)the Natural Science Foundation of Guizhou Provincial Education Department,China(Grant No.KY[2013]183)the Research Fund for the Doctoral Program of Tongren University,China(Grant Nos.DS1302 and trxy S1415)
文摘In this paper, diamond crystallization from carbonyl nickel powders-C and carbonyl nickel powders + Fe–C systems are investigated in detail at a pressure of 6.0 GPa and temperatures ranging from 1410°C–to 1435°C by temperature gradient growth. The effects of Fe additive on the crystal morphology are discussed in the diamond crystallization process.Furthermore, Fourier infrared measurement results indicate that the spectrum of the diamond obtained from Ni + Fe–C system after annealing treatment is nearly consistent with that of natural diamond crystal. We believe that this study is of benefit to a further understanding of the growth mechanism of natural diamond.
文摘Diamond polycrystal powder has been produced directly from gas phase in an arc discharge plasma jet system.Acetylene diluted in argon was used as hydrocarbon source gas.The product was the mixture of diamond polycrystal powders and soot.The 3C cubic phase diamond which is dominant,and the mixture phases of cubic and 6H hexagonal diamond are identified in the produced diamond polycrystal powders by electron diffraction patterns.
文摘A numerical investigation was carried out to examine the role of micro-sized diamond powder filler on the on-axis tensile stiffness properties of the standard modulus T300 and the high modulus YS90A woven fabric composite plates by progressive damage modeling. Finite element modeling (FEM) results for the T300 composite with and without diamond powder predicted a specific case of fiber failure in all the plies showing the characteristics of brittle failure. Static tensile tests were carried out on the YS90A composite coupons containing no diamond powder (DP) and filled with 6% and 12% volume fractions of DP. A higher content of diamond powder in the coupons led to agglomeration. This induced stress concentrations and subsequently reduced the mechanical properties. FEM was carried out considering specimens with and without an induced stress concentration geometry in the YS90A coupons filled with DP. The results of the on-axis tensile tests indicated a delamination type of failure in both cases with additional fiber fracture in the Open Hole Tensile (OHT) coupons.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50502026), the Chinese 863 Program (No. 2002AA302504), the Science Foundation of Wuhan University of Technology (No. xjj2005166), and the Key Project for Science and Technology Development of Wuhan City (No. 20041003068-04)
文摘Nanocrystalline WC-Co composite powder and coated tungsten diamond by using vacuum vapor deposition were consolidated by the spark plasma sintering （SPS） process to prepare diamond-enhanced WC-Co cemented carbide composite materials. The interface microstructures between coated tungsten diamond and WC-Co cemented carbide matrix were investigated by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDXS）. The results showed that there is a transitional layer between the diamond and the matrix, in which the carbon content is 62.97wt.%, and the content of cobalt in the transitional zone is 6.19wt.%; the content of cobalt in the WC-Co cemented carbide matrix is 6.07wt.%, in which the carbon content is 15.95wt.%, and the content of cobalt on the surface of diamond is 7.30wt.%, in which the carbon content is 80.38wt.%. The transitional zone prevents the carbon atom of the diamond from spreading to the matrix, in which the carbon content does coincide with the theoretical value of the raw nanocomposite powders, and the carbon content forms a graded distribution among the matrix, transitional zone, and the surface of diamond; after the 1280℃ SPS consolidated process the diamond still maintains a very good crystal shape, the coated tungsten on the surface of the diamond improves thermal stability of the diamond and increases the bonding strength of the interface between the diamond and the matrix.
