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Liang Wang - One of the best experts on this subject based on the ideXlab platform.
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new utilization approach of microwave thermal energy preparation of Metallic Matrix diamond tool bit by microwave hot press sintering
Journal of Alloys and Compounds, 2018Co-Authors: Shenghui Guo, Li Yang, Jiyun Gao, Jinhui Peng, Liang Wang, Ming Hou, Qiyue LuoAbstract:Abstract Sintering is a critical process for the preparation of Metallic Matrix diamond tools. The purpose of this work aims to propose a novel microwave hot-press sintering (MHPS) method for the improvement of mechanical properties for Fe-Cu-W-Sn Matrix diamond tools. The samples were prepared by MHPS and conventional hot-press sintering (CHPS), respectively. The microstructures of samples were characterized using XRD, EMPA, and SEM tests. The mechanical properties of samples, such as relative density, hardness, bending strength, and impact toughness were also investigated. Experimental results show that the samples by MHPS method has obvious advantages with shorter sintering time, lower sintering temperature, more uniform element diffusion, and better holding situation of diamond abrasives in the alloyed Matrix. The optimal mechanical properties of samples sintered by MHPS at 850 °C, to be specific, including relative density, hardness and flexural strength reach 97.8%, 99.2 HRB and 986 MPa, respectively. The possible mechanism of MHPS is discussed. This work can provide a reference for microwave sintering of Metallic Matrix diamond tools.
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Optimization of Process Parameters for Preparing Metallic Matrix Diamond Tool Bits by Microwave Pressureless Sintering Using Response Surface Methodology
MDPI AG, 2018Co-Authors: Li Yang, Shenghui Guo, Jiyun Gao, Liang Wang, Sivasankar Koppala, Ming HouAbstract:The process of preparing Metallic Matrix diamond tool bits by microwave pressureless sintering (MPS) was exclusively studied in this paper. The effects of the sintering temperature, the cold pressure, and the holding time on the mechanical properties of the bit were determined by using the response surface methodology (RSM) with Box-Behnken Design (BBD). In addition, with RSM, the second-order polynomial equation of mechanical properties was obtained. The solutions were well matched with the experimental values. This indicates that major variations in mechanical properties of the sintered sample could be predicted by the models, which shows that the applied model is accurate. Conventional pressureless sintering (CPS) experiments were also conducted to make a comparison. The experimental results showed that the MPS can enhance the mechanical properties of sintered samples. A possible MPS mechanism is proposed in this work after analyzing all the experimental results
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formation mechanism of ohmic contacts on algan gan heterostructure electrical and microstructural characterizations
Journal of Applied Physics, 2008Co-Authors: Liang Wang, Fitih M Mohammed, I AdesidaAbstract:The electrical characteristics and interfacial reactions of Ti∕Al∕Mo∕Au metallization on AlGaN∕GaN heterostructures at various annealing temperatures ranging from 400to950°C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky to Ohmic electrical behavior occurred at ∼500°C. This transition was engendered by the formation of a thin epitaxial TiN layer on the AlGaN. Binary and ternary interMetallic compound formations were observed to have formed as a result of intermixing and reactions among the metals. The Mo layer remained continuous until 700°C, where it disintegrated into particles embedded in the Metallic Matrix. An optimal contact performance was obtained for Ti∕Al∕Mo∕Au on AlGaN∕GaN at 850°C; this was correlated to TiN island formation along dislocations penetrating into the heterostructure beyond the plane of the two-dimensional electron gas. Overannealing degradation mechanism at 950°C is also explained based on structural characteriza...
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formation mechanism of ohmic contacts on algan gan heterostructure electrical and microstructural characterizations
Journal of Applied Physics, 2008Co-Authors: Liang Wang, Fitih M Mohammed, I AdesidaAbstract:The electrical characteristics and interfacial reactions of Ti∕Al∕Mo∕Au metallization on AlGaN∕GaN heterostructures at various annealing temperatures ranging from 400to950°C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky to Ohmic electrical behavior occurred at ∼500°C. This transition was engendered by the formation of a thin epitaxial TiN layer on the AlGaN. Binary and ternary interMetallic compound formations were observed to have formed as a result of intermixing and reactions among the metals. The Mo layer remained continuous until 700°C, where it disintegrated into particles embedded in the Metallic Matrix. An optimal contact performance was obtained for Ti∕Al∕Mo∕Au on AlGaN∕GaN at 850°C; this was correlated to TiN island formation along dislocations penetrating into the heterostructure beyond the plane of the two-dimensional electron gas. Overannealing degradation mechanism at 950°C is also explained based on structural characterization.The electrical characteristics and interfacial reactions of Ti∕Al∕Mo∕Au metallization on AlGaN∕GaN heterostructures at various annealing temperatures ranging from 400to950°C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky to Ohmic electrical behavior occurred at ∼500°C. This transition was engendered by the formation of a thin epitaxial TiN layer on the AlGaN. Binary and ternary interMetallic compound formations were observed to have formed as a result of intermixing and reactions among the metals. The Mo layer remained continuous until 700°C, where it disintegrated into particles embedded in the Metallic Matrix. An optimal contact performance was obtained for Ti∕Al∕Mo∕Au on AlGaN∕GaN at 850°C; this was correlated to TiN island formation along dislocations penetrating into the heterostructure beyond the plane of the two-dimensional electron gas. Overannealing degradation mechanism at 950°C is also explained based on structural characteriza...
I Adesida - One of the best experts on this subject based on the ideXlab platform.
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formation mechanism of ohmic contacts on algan gan heterostructure electrical and microstructural characterizations
Journal of Applied Physics, 2008Co-Authors: Liang Wang, Fitih M Mohammed, I AdesidaAbstract:The electrical characteristics and interfacial reactions of Ti∕Al∕Mo∕Au metallization on AlGaN∕GaN heterostructures at various annealing temperatures ranging from 400to950°C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky to Ohmic electrical behavior occurred at ∼500°C. This transition was engendered by the formation of a thin epitaxial TiN layer on the AlGaN. Binary and ternary interMetallic compound formations were observed to have formed as a result of intermixing and reactions among the metals. The Mo layer remained continuous until 700°C, where it disintegrated into particles embedded in the Metallic Matrix. An optimal contact performance was obtained for Ti∕Al∕Mo∕Au on AlGaN∕GaN at 850°C; this was correlated to TiN island formation along dislocations penetrating into the heterostructure beyond the plane of the two-dimensional electron gas. Overannealing degradation mechanism at 950°C is also explained based on structural characteriza...
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formation mechanism of ohmic contacts on algan gan heterostructure electrical and microstructural characterizations
Journal of Applied Physics, 2008Co-Authors: Liang Wang, Fitih M Mohammed, I AdesidaAbstract:The electrical characteristics and interfacial reactions of Ti∕Al∕Mo∕Au metallization on AlGaN∕GaN heterostructures at various annealing temperatures ranging from 400to950°C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky to Ohmic electrical behavior occurred at ∼500°C. This transition was engendered by the formation of a thin epitaxial TiN layer on the AlGaN. Binary and ternary interMetallic compound formations were observed to have formed as a result of intermixing and reactions among the metals. The Mo layer remained continuous until 700°C, where it disintegrated into particles embedded in the Metallic Matrix. An optimal contact performance was obtained for Ti∕Al∕Mo∕Au on AlGaN∕GaN at 850°C; this was correlated to TiN island formation along dislocations penetrating into the heterostructure beyond the plane of the two-dimensional electron gas. Overannealing degradation mechanism at 950°C is also explained based on structural characterization.The electrical characteristics and interfacial reactions of Ti∕Al∕Mo∕Au metallization on AlGaN∕GaN heterostructures at various annealing temperatures ranging from 400to950°C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky to Ohmic electrical behavior occurred at ∼500°C. This transition was engendered by the formation of a thin epitaxial TiN layer on the AlGaN. Binary and ternary interMetallic compound formations were observed to have formed as a result of intermixing and reactions among the metals. The Mo layer remained continuous until 700°C, where it disintegrated into particles embedded in the Metallic Matrix. An optimal contact performance was obtained for Ti∕Al∕Mo∕Au on AlGaN∕GaN at 850°C; this was correlated to TiN island formation along dislocations penetrating into the heterostructure beyond the plane of the two-dimensional electron gas. Overannealing degradation mechanism at 950°C is also explained based on structural characteriza...
G Sharp - One of the best experts on this subject based on the ideXlab platform.
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nature of surface changes in stamping tools of gray and ductile cast iron during gas and plasma nitrocarburizing
Journal of Materials Engineering and Performance, 2009Co-Authors: E Rolinski, A Konieczny, G SharpAbstract:Two cast irons, pearlitic-ferritic gray and ferritic ductile, were plasma and gas nitrocarburized at the same temperature and for the same processing time to produce a compound zone of about 10-14 μm thick. It was demonstrated that both processes caused changes in the surface roughness of the irons, and the most dramatic increase of roughness was observed after gas nitrocarburizing of the gray cast iron. It was shown that the primary reason that the results were not the same is the difference in the nitriding mechanism. Significant penetration of the surface voids and imperfections between the graphite particles and the Metallic Matrix by ammonia molecules led to the formation of a locally thicker compound zone and a bulging of the Metallic Matrix above the surface. This phenomenon did not occur in the plasma process and as a result the surface changes were much smaller than in the gas process.
E Rolinski - One of the best experts on this subject based on the ideXlab platform.
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nature of surface changes in stamping tools of gray and ductile cast iron during gas and plasma nitrocarburizing
Journal of Materials Engineering and Performance, 2009Co-Authors: E Rolinski, A Konieczny, G SharpAbstract:Two cast irons, pearlitic-ferritic gray and ferritic ductile, were plasma and gas nitrocarburized at the same temperature and for the same processing time to produce a compound zone of about 10-14 μm thick. It was demonstrated that both processes caused changes in the surface roughness of the irons, and the most dramatic increase of roughness was observed after gas nitrocarburizing of the gray cast iron. It was shown that the primary reason that the results were not the same is the difference in the nitriding mechanism. Significant penetration of the surface voids and imperfections between the graphite particles and the Metallic Matrix by ammonia molecules led to the formation of a locally thicker compound zone and a bulging of the Metallic Matrix above the surface. This phenomenon did not occur in the plasma process and as a result the surface changes were much smaller than in the gas process.
Fitih M Mohammed - One of the best experts on this subject based on the ideXlab platform.
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formation mechanism of ohmic contacts on algan gan heterostructure electrical and microstructural characterizations
Journal of Applied Physics, 2008Co-Authors: Liang Wang, Fitih M Mohammed, I AdesidaAbstract:The electrical characteristics and interfacial reactions of Ti∕Al∕Mo∕Au metallization on AlGaN∕GaN heterostructures at various annealing temperatures ranging from 400to950°C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky to Ohmic electrical behavior occurred at ∼500°C. This transition was engendered by the formation of a thin epitaxial TiN layer on the AlGaN. Binary and ternary interMetallic compound formations were observed to have formed as a result of intermixing and reactions among the metals. The Mo layer remained continuous until 700°C, where it disintegrated into particles embedded in the Metallic Matrix. An optimal contact performance was obtained for Ti∕Al∕Mo∕Au on AlGaN∕GaN at 850°C; this was correlated to TiN island formation along dislocations penetrating into the heterostructure beyond the plane of the two-dimensional electron gas. Overannealing degradation mechanism at 950°C is also explained based on structural characteriza...
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formation mechanism of ohmic contacts on algan gan heterostructure electrical and microstructural characterizations
Journal of Applied Physics, 2008Co-Authors: Liang Wang, Fitih M Mohammed, I AdesidaAbstract:The electrical characteristics and interfacial reactions of Ti∕Al∕Mo∕Au metallization on AlGaN∕GaN heterostructures at various annealing temperatures ranging from 400to950°C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky to Ohmic electrical behavior occurred at ∼500°C. This transition was engendered by the formation of a thin epitaxial TiN layer on the AlGaN. Binary and ternary interMetallic compound formations were observed to have formed as a result of intermixing and reactions among the metals. The Mo layer remained continuous until 700°C, where it disintegrated into particles embedded in the Metallic Matrix. An optimal contact performance was obtained for Ti∕Al∕Mo∕Au on AlGaN∕GaN at 850°C; this was correlated to TiN island formation along dislocations penetrating into the heterostructure beyond the plane of the two-dimensional electron gas. Overannealing degradation mechanism at 950°C is also explained based on structural characterization.The electrical characteristics and interfacial reactions of Ti∕Al∕Mo∕Au metallization on AlGaN∕GaN heterostructures at various annealing temperatures ranging from 400to950°C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky to Ohmic electrical behavior occurred at ∼500°C. This transition was engendered by the formation of a thin epitaxial TiN layer on the AlGaN. Binary and ternary interMetallic compound formations were observed to have formed as a result of intermixing and reactions among the metals. The Mo layer remained continuous until 700°C, where it disintegrated into particles embedded in the Metallic Matrix. An optimal contact performance was obtained for Ti∕Al∕Mo∕Au on AlGaN∕GaN at 850°C; this was correlated to TiN island formation along dislocations penetrating into the heterostructure beyond the plane of the two-dimensional electron gas. Overannealing degradation mechanism at 950°C is also explained based on structural characteriza...