Low Pressure Infiltration Process Research Articles

Simulation and Experimental of Infiltration and Solidification Process for Al2O3(3D)/5083Al Interpenetrating Phase Composite for High Speed Train Prepared by Low-Pressure Infiltration.

Understanding the infiltration and solidification processes of liquid 5083Al alloy into Al2O3 three-dimensional reticulated porous ceramic (Al2O3(3D) RPC) is essential for optimizing the microstructure and properties of Al2O3(3D)/5083Al interpenetrating phase composites (IPCs) prepared by low-pressure infiltration process (LPIP). This study employs ProCAST software to simulate the infiltration and solidification processes of liquid 5083Al with pouring velocities (PV) of 0.4 m/s infiltrating into Al2O3(3D) RPC preforms with varying porosities at different pouring temperatures (PT) to prepare Al2O3(3D)/5083Al IPCs using LPIP. The results demonstrate that pore diameter of Al2O3(3D) RPC preforms and PT of liquid 5083Al significantly influence the of the infiltration. Solidification process analysis reveals that the Al2O3(3D) RPC preform with smaller pore diameters allows the lower pouring velocity of 5083Al to solidify faster compared to the preform with larger pore diameters. Al2O3(3D)/5083Al IPCs were prepared successfully from Al2O3(3D) RPC porosity of 15 PPI with liquid 5083Al at PV 0.4 m/s and PT 800 °C using LPIP, resulting in nearly fully dense composites, where both Al2O3(3D) RPCs and 5083Al interpenetrate throughout the microstructure. The infiltration and solidification defects were reduced under air pressure of 0.3 MPa (corresponding to PV of 0.4 m/s) during LPIP. Finite volume method simulations are in good agreement with experimental data, validating the suitability of the simplified model for Al2O3(3D) RPCs in the infiltration simulation.

Development Of Short Carbon Fiber Reinforced Aluminium Matrix Composites By Low Pressure Infiltration Process

Short carbon fiber reinforced aluminium based matrix composites were fabricated by a low-pressure infiltration process. This study is amid for development of short carbon fiber reinforced aluminium matrix composites. Short carbon fibers of 10 vol.% was used to preparing preforms for the low-pressure infiltration process. Afterwards, pure Al and Aluminium alloy under temperature of 1073K were infiltrated into the preforms under an applied pressure of 0.4MPa. Microstructure and Vickers hardness as well as microstructure–property relationships of these materials were studied. Microstructure observations indicated that: the SiO2 binder was coating on the surface of short carbon fiber and distributed at the corner of carbon fibers in preforms. Short carbon fibers were homogeneously distributed in the matrix. Furthermore, properties of short carbon fiber reinforced pure Al and A336 alloy composites showed that: the relative density was 95.8% and 97.2%, respectively. Hardness of short carbon fiber reinforced pure Al composite increased by 76% comparing to the base pure Al, and short carbon fiber reinforced A336 alloy composite increased by 10% comparing to the A336 alloy.

Microstructures of Carbon Fiber and Hybrid Carbon Fiber-Carbon Nanofiber Reinforced Aluminum Matrix Composites by Low Pressure Infiltration Process and Their Properties

Microstructures of Carbon Fiber and Hybrid Carbon Fiber-Carbon Nanofiber Reinforced Aluminum Matrix Composites by Low Pressure Infiltration Process and Their Properties

Wear behavior of Al2O3/AC8A composites by low pressure infiltration process

Wear behavior of Al2O3/AC8A composites by low pressure infiltration process

Wear behavior of Ni and Ni-Cr enhanced AC8A composites by low pressure infiltration process

Wear behavior of Ni and Ni-Cr enhanced AC8A composites by low pressure infiltration process

Development of vapour-grown carbon nano-fibre-reinforced aluminium matrix composites by low-pressure infiltration process

This study was aimed for development of vapour-grown carbon nano-fibre(VGCNF)-reinforced aluminium matrix composites by the low-pressure infiltration process. First, VGCNF and Al powder (VGCNF + Alp) preforms for low-pressure infiltration were fabricated by spark sintering process at pressures of 5, 10, 20 and 40 MPa, respectively. Porosity of the preforms fabricated at pressures of 5 and 10 MPa was 44·89 and 40·87%, respectively. However, porosity of the preforms fabricated by spark sintering at pressures of 20 and 40 MPa was approximately 20%. Therefore, VGCNF + Alp/Al composites with the preform sintered at pressures of 5 and 10 MPa were fabricated by the low-pressure infiltration process under an applied pressure of 0·4 MPa, and the relative density was 81·4 and 76·0%, respectively. Moreover, the microstructure, porosity and electrical conductivity of the VGCNF + Alp/Al composites were estimated. Their electrical conductivities reduced with increasing porosity of VGCNF + Alp/Al composites.

Influence of Si addition on thermal conductivity of unidirectional CF/Al-Si composites fabricated by low pressure infiltration process

Unidirectional CF/Al-Si composites were fabricated by low pressure infiltration, permeating molten Al into porous CF-Si preform. In this study, the influences of Si addition in the preforms on the thermal conductivity of obtained CF/Al-Si composites were investigated in terms of the degradation of high thermal conductive CFs by chemical reactions in Si-C and Al-C systems. Comparing with theoretical value, the thermal conductivity of CF/Al-Si composites was extremely low. Although the Si-C reaction led to the decrease of the thermal conductivity, the sintered Si around CF surfaces protected from the significant decrease of the thermal conductivity being attributed to the severe Al and CF reaction. The surface damage of high thermal conductive CFs by Al-C reaction became a main reason for the decrease in the thermal conductivity of CF/Al-Si composites. Especially, the active Al-C reaction in the region of extremely low Si content around CF surfaces affected significant degradation of the CFs.

Influence of Interfacial Reaction on Wear Resistance of Aluminum Alloy/SiC Composites Fabricated by Low Pressure Infiltration Process

Influence of Interfacial Reaction on Wear Resistance of Aluminum Alloy/SiC Composites Fabricated by Low Pressure Infiltration Process

Influence of the specific surface area of a porous nickel to the intermetallic compound generated by reaction of a porous nickel and aluminum

A new process is proposed to fabricate an intermetallic compound reinforced aluminum alloy matrix composite by using the reaction between porous nickel and molten aluminum alloy. The intermetallic compound reinforced aluminum alloy composite was manufactured with the low-pressure infiltration process method. The amounts of the intermetallic compounds under 3 different specific surface area of porous nickel and the porosity inside composites were investigated. Porous nickel reacted with molten aluminum alloy at 973 K, and the intermetallic compound of Al3Ni was generated on the surface of the porous nickel. The generated intermetallic compound Al3Ni, was delaminated according to the difference of thermal expiation coefficient with nickel. And the intermetallic compounds moves in the direction of aluminum matrix. The area fraction of the intermetallic compounds increased with the increasing specific surface area of porous nickel. In addition, the defect inside the composite decreased by the increasing specific surface area of porous nickel.

Synergy effect of reinforcement particle, fiber and matrix on wear resistance of hybrid metal matrix composite fabricated by low pressure infiltration process

Abstract Alumina fiber (Al 2 O 3f ) and alumina particle (Al 2 O 3p ) reinforced Al–4mass%Cu alloy matrix composites (Hybrid-MMC) have been fabricated by a low pressure infiltration process. Total amount of reinforcements is fixed to be 20 vol.% and the range of the amounts of Al 2 O 3f and Al 2 O 3p is varied from 7.5 vol.% to 12.5 vol.%. When the ratio of fiber vol.% to particle vol.% is increased, the soundness of casting has improved. The Hybrid-MMC with 12.5 vol.% Al 2 O 3f and 7.5 vol.% Al 2 O 3p has better wear resistance compared with PRMMC with 20 vol.% Al 2 O 3p and FRMMC with 20 vol.% Al 2 O 3f . The excellent Hybrid-MMC is attributable to a synergy effect of Al 2 O 3 particles and Al 2 O 3 fibers having a 3-D distribution, which protects Al 2 O 3 particles from dropping out. A superior wear resistance has been observed in the MMC with an age-hardened Al–Cu matrix and another synergy effect of reinforcements and matrix is observed.

Effect of aluminum carbide on thermal conductivity of the unidirectional CF/Al composites fabricated by low pressure infiltration process

The coal-tar pitch based carbon fiber reinforced aluminum (CF/Al) composite material is one of the potential candidates of heat dissipation components for its high thermal conductivity (TC). Low pressure infiltration (LPI) method is a useful casting process for fabrication of CF/Al composites with its cost-effectiveness by using extremely low pressure. However, the detrimental product of the reaction between aluminum alloy and CF, such as aluminum carbide (Al 4 C 3 ), is able to affect not only mechanical properties but also TC of CF/Al composites. In the present study, the effect of the growth of Al 4 C 3 during LPI process on TC of unidirectional (UD) CF/Al composites has been characterized. The variation of longitudinal TC was sensitive to growth of Al 4 C 3 during ‘cooling process’ of LPI, whereas the longitudinal TC was not influenced by that during ‘infiltration process’ mostly. The progress of local damages on CF surfaces caused by Al 4 C 3 growth during ‘cooling process’ was a main reason of the decreasing of the longitudinal TC of UD-CF/Al composites.

Fabrication of Continuous Nickel-Coated Carbon Fiber Reinforced Aluminum Matrix Composites Using Low Gas Pressure Infiltration Method

Based on the principle of vacuum counter-pressure casting, a low gas pressure infiltration technology was developed to fabricate the Ni-coated carbon fiber reinforced A357 alloy composites. The soundness and microstructure of the as-cast composites were investigated. The results show the relative density increases with the increase of melt temperature, while it firstly increases and then declines as the fiber temperature and infiltration pressure increased. The enhancement of melt and fiber temperature can eliminate the incomplete infiltration defects and improve the uniformity of fiber distribution. The insufficient infiltration pressure leads to some micro-pores in the matrix alloy. However, the over high fiber temperature and infiltration pressure may result in the separation of nickel coating and the fiber aggregation respectively, both of which are responsible for the partial un-infiltrated or insufficient filling defects. The appropriate infiltration parameters identified in this study could provide a reference for inhibition of the hazard interfacial reactions by optimizing the low gas pressure infiltration process.

114 低圧含浸法による高熱伝導CF/Al複合材料の作製

114 低圧含浸法による高熱伝導CF/Al複合材料の作製

Microstructure and Hardness of Ni-Cr Porous Preform Reinforced Al-Based Composites by Low Infiltration Method

With the rapid development of aerospace and automobile industries, metal matrix composites (MMCs) have attracted much attention because of its excellent performance. In this paper, Ni-Cr/AC8A composites reinforced with porous Ni-Cr preform were manufactured by low pressure infiltration process, infiltration temperatures are 700oC~850oC. The microstructure and phase composition of composites were evaluated using optical microscope, X-ray diffraction (XRD) and electro-probe microanalysis (EPMA), It's found that they're intermetallic compounds generated in the composites. Recently, intermetallic compounds have attracted much attention as high-temperature material. We study the hardness of Ni-Cr/AC8A composites, the results show the Ni-Cr/AC8A composite has high hardness due to the intermetallic compounds exist.

Effect of Alumina Fibers on Fabrication Process and Characteristics of Alumina Fiber Reinforced Aluminum Alloy Composites

In order to develop the alumina fiber reinforcements optimized to FRMMCs, the effect of characteristics of alumina fibers on the fabrication process and the characteristics of the alumina fiber reinforced Al alloy composites was investigated. Alumina fibers which have different alumina content were prepared. Alumina content in the fibers was varied from 80% to 100%. Al-4mass%Cu alloy, Al-12mass%Si alloy and Al-10masss%Mg alloy were used as matrix. The FRMMC specimens were fabricated by a low-pressure infiltration process (LPI process). The formability of the preform was improved with increasing alumina content in the fibers. However, broken fibers were observed in the preform when alumina fibers with high alumina content were used. The number of the broken fibers seemed to be increased with increasing alumina content in the fibers. This result could be attributable to a change of fiber strength resulting from a change of alumina content in the fiber. The FRMMC specimens were characterized by using Vickers hardness test. The Vickers hardness of FRMMC specimens depended on the elasticity or the hardness of the fibers. The results obtained suggest that the characteristics of the FRMMCs largely depend on the intrinsic characteristics of the reinforcement fibers.

Separation of PRMMC into matrix alloy and reinforcements by nozzle filtering method

The SiC P/Al–4 mass%Cu alloy composites fabricated by a low-pressure infiltration process (LPI process) were remelted and separated by nozzle filtering method. In the separation process, the PRMMC specimen was placed in a container with a small nozzle at the bottom. The molten PRMMC was forced to flow out through the nozzle by applying a certain pressure of Ar gas. Most of the molten matrix alloy flowed out through the nozzle and the remainder in the container consisted of SiC particles and a part of the matrix alloy. The particle volume fraction of the remainder was higher than that of the original PRMMC and the remainder would work as a filter to separate SiC particles from the matrix alloy melt. When nozzle tip angle was ranged from 60° to 120°, about 80% of matrix alloy in the PRMMC was separated and few SiC particles were observed in the separated matrix alloy. The surface of recovered SiC particles became slightly roughened due to the reaction with the molten matrix during the separation process. However, this is not expected to affect their reuse.

A study on the manufacturing conditions of metal matrix composites by low pressure infiltration process

Metal fiber preform reinforced aluminum alloy composite as made by the infiltration of molten metal under low pressure casting process. The infiltration behavior of filling pattern and the velocity profile with low-pressure casting process was investigated. The thermocouple was inserted into the preform in order to observe the infiltration behavior. The infiltration of applied pressure time, 1, 2 and 5 s under constant pressure of 0.4 MPa was completely filled during 0.4 s. In these conditions, molten aluminum alloy has successfully infiltrated to FeCrSi metal fiber preform by low-pressure casting process. It was observed the porosity of composites for reliability of composites. The automobile piston was developed with FeCrSi reinforced aluminum alloy that is 0% porosity by the optimal applied pressure and applied pressure time.

Characterization of fiber-reinforced metal matrix composites fabricated by low-pressure infiltration process

The physical and mechanical properties of randomly oriented fiber-reinforced metal matrix composites (FRMMCs) fabricated by LPI process were examined. SiC particles and SiC fibers were used as reinforcement, while Al–4 mass% Cu alloy, Al–7 Si mass% alloy and AZ91 alloy were used as matrix. A mixture consisting of aluminum particles, SiC particles and SiC fibers was prepared as a preform to control the distribution of SiC fibers in FRMMC. Randomly oriented FRMMC specimens were fabricated by infiltrating the molten matrix alloy into the preform by pressing the melt surface with a low pressure of Ar gas. FRMMC specimens showed a high performance in thermal cycling test as well as an excellent wear resistance. The Vickers hardness of FRMMC specimens was almost constant on the different sections and the physical and mechanical properties were found to be isotropic.

Fiber Orientation Control and Evaluation of Characteristics of Short Fiber Reinforced Metal Matrix Composite Fabricated by Low-Pressure Infiltration Process

Fiber Orientation Control and Evaluation of Characteristics of Short Fiber Reinforced Metal Matrix Composite Fabricated by Low-Pressure Infiltration Process

Thermal Expansion Behavior of SiCP/Aluminum Alloy Composites Fabricated by a Low-Pressure Infiltration Process

Thermal cycling test was carried out for 20 vol% and 40 vol% SiC particle/Al-4 mass%Cu alloy composites to evaluate the bonding strength of the SiC particle/matrix interface in PRMMC fabricated by a low-pressure infiltration process (LPI process). The SiC particles were distributed homogenously in the specimens and a reaction layer of less than I μm thickness was observed at the SiC particle/matrix interface before thermal cycling test. This reaction layer was identified as Al 4 C 3 formed by the reaction between the alloy melt and SiC particle during infiltration. The θ phase, which might form a coherent interface with Al 4 C 3 , crystallized around the SiC particles through the Al 4 C 3 layer. The coefficient of thermal expansion was hardly changed during thermal cycling for both the 20 vol% and 40 vol% SiC particle/Al-Cu composites. No significant change in the microstructure and no detachment at the SiC particle/matrix interface were observed after thermal cycling test. The interfacial structure consisting of SiC. Al 4 C 3 , θ phase and α-Al in order was considered to exhibit a strong bonding of SiC particles to the matrix. The Vickers microhardness measured on the SiC particles in the specimens having a strongly bound interface show hardness values with a small scatter, while those for the specimens having a weakly bound interface exhibit a large scatter in the hardness values. It is suggested that the bonding strength of the reinforcement particle/matrix interface could be ascribed qualitatively from the Vickers microhardness test.