Fabrication and Bending Strength of Al/SiC Composites with High Volume Fraction of Reinforcement by Combining Powder Injection Molding and Pressure Infiltration

2011 ◽  
Vol 189-193 ◽  
pp. 2945-2948
Author(s):  
Liang Xiong ◽  
Hao He ◽  
Yi Min Li
Keyword(s):  
Particle Size ◽  
Injection Molding ◽  
Bending Strength ◽  
Volume Fraction ◽  
High Volume ◽  
Powder Injection Molding ◽  
High Volume Fraction ◽  
Powder Injection ◽  
Pressure Infiltration ◽  
Sic Composites

The paper presents the result of an experimental investigation on the fabrication of Al/SiC composites with high volume fraction of SiC particles by pressure infiltration of liquid aluminum into preforms prepared by powder injection molding (PIM). To obtain the required high particle volume fraction, SiC powders with a bimodal particle size distribution were used. The influence of powder loading and particle size on the bending strength of the prepared composites has been investigated. It is demonstrated that pressure infiltration permits to achieve high relative densities for the composites (i.e. 98.8%). The microstructure studies revealed a uniform distribution of SiC particles in the composites without interface reactions between the particles and the aluminum matrix. The bending strength increases with increasing powder loading and decreasing particle size of the coarse powders in the bimodal powder system.

Thermo-Physical Properties of SiCAl Composites with High Volume Fraction of Reinforcement Prepared by Combining Powder Injection Molding and Pressure Infiltration

2011 ◽  
Vol 239-242 ◽  
pp. 1832-1837
Author(s):  
Hao He ◽  
Yi Min Li
Keyword(s):  
Particle Size ◽  
Injection Molding ◽  
Physical Properties ◽  
Volume Fraction ◽  
High Volume ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Pressure Infiltration ◽  
Johnson Model ◽  
Thermo Physical Properties

SiC/Al composites with high reinforcement content were fabricated by pressure infiltration of aluminum alloy into porous SiC preform obtained by powder injection molding using a bimodal powder mixture. The influence of powder loading and particle size on the thermo-physical properties of the prepared composites was investigated. The results indicate that the thermal conductivities (TC) increases and coefficients of thermal expansion (CTE) decreases with increasing powder loading and particle size of the coarse powders in the bimodal powder system. The TCs are below the estimated value based on Hasselman-Johnson model, mainly due to the residual pores and the irregular particle shape. The CTEs of the composites increase with increasing temperature from 100°C to 400°C, and the increasing rates vary at different temperature ranges. Deep cooling in liquid nitrogen is effective to bring dislocations in the matrix and thus reduces the CTEs.

Study on Removal Mechanism and Surface Quality of High Volume Fraction SiCp/Al Composites Based on Meso-scale

2021 ◽  
Author(s):  
Po Jin ◽  
Qi Gao ◽  
Quanzhao Wang ◽  
Wenbo Li
Keyword(s):  
Particle Size ◽  
Surface Quality ◽  
Feed Rate ◽  
Volume Fraction ◽  
High Volume ◽  
Milling Process ◽  
Subsurface Damage ◽  
High Volume Fraction ◽  
Removal Mechanism

Abstract The milling process of SiCp/Al composites with high volume fraction and large particle size has been studied in this paper. The stress and strain distribution of SiC reinforced particles and the removal mechanism of the material are analysed. The effects of milling depth and feed per tooth on surface quality were analysed. The effect of feed per tooth on the thickness of subsurface damage layer is revealed. The results show that in the end milling process of high volume fraction SiCp/Al composites, the blade diameter is larger relative to the particle size, which leads to the main removal forms of particle size: extrusion crushing and rolling crushing. The surface defects of the machined workpiece mainly include cavity, crack and delamination caused by extrusion of aluminum matrix. The surface quality of the machined workpiece can be improved by increasing the milling depth appropriately. The increase of the feed rate of each tooth will lead to the increase of the surface defect of the machined workpiece and the deterioration of the surface quality. When the feed rate per tooth increases from 4 to 8 μm, the thickness of subsurface damage increases from 47.7 to 60.5 μm. It is found that the ratio between the minimum cutting thickness of SiCp/Al composites and the radius of the cutting edge should be less than or equal to 4%.

Analysis of Powder Segregation in Powder Injection Molding

2011 ◽  
Vol 217-218 ◽  
pp. 1372-1379
Author(s):  
Yu Hui Wang ◽  
Xuan Hui Qu ◽  
Wang Feng Zhang ◽  
Yan Li
Keyword(s):  
Fluid Flow ◽  
Injection Molding ◽  
Volume Fraction ◽  
Fluid Model ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Exchange Term ◽  
Mixture Density ◽  
Two Fluid Model ◽  
Two Fluid

The powder injection molding (PIM) combines the thermoplastic and powder metallurgy technologies to manufacture intricate parts to nearly shape. The powder segregation is a special effect arising in PIM different from than the pure polymer injection. The two-fluid flow model is used to describe the flows of binder and powder so as to realize the prediction of powder segregation effect in PIM injection. To take into account binder–powder interaction, the mixture model of inter-phase exchange term is introduced in the two-fluid model. The two-fluid equations largely resemble those for single-fluid flow but are represented in terms of the mixture density and velocity. The volume fraction for each dispersed phase is solved from a phase continuity equation. As the key to calculate the phase exchange term, the drag coefficient is defined as a function of mixture viscosity. The effective viscosity of binder and powder are agreed with the additive principle. The volume fractions of binder and powder give directly the evolution of segregation during the injection course. Segregation during PIM injection was simulated by software CFX and results were compared with experimental data with good agreement. The basic reasons that caused segregation are identified as boundary effect, differences in density and viscosity of binder and powder. The segregation zones are well predicted. This showed that the two-fluid model is valid and efficient for the prediction of the segregation effects in PIM injection.

A Study on the SiC/Al Composites Fabricated by Pressureless Infiltration

2008 ◽  
Vol 569 ◽  
pp. 189-192
Author(s):  
Ke Zheng Sang ◽  
Chun Feng Wan
Keyword(s):  
Particle Size ◽  
Volume Fraction ◽  
High Volume ◽  
High Volume Fraction ◽  
Pressureless Infiltration ◽  
Green Body ◽  
Sic Particles

SiC/Al composites with high volume fraction of SiC were prepared at 1150°C by pressureless infiltration. The volume fraction of SiC was increased by decreasing the amount of starch in the green body. Both the microstructure and the strength of the composites were investigated. The results showed that the strength decreased with the increasing of the particle size and volume fraction of SiC. It was suggested that the interface between the SiC particles, which were not sintered, make of the defects in the composites. The defects led to the decreasing of the strength with increasing of the volume fraction of SiC.

scholarly journals Effects of Cr and B Contents on Volume Fraction of (Cr,Fe)2B and Hardness in Fe-Based Alloys Used for Powder Injection Molding

2012 ◽  
Vol 43 (7) ◽  
pp. 2237-2250 ◽  
Author(s):  
Jeonghyeon Do ◽  
Hyuk-Joong Lee ◽  
Changwoo Jeon ◽  
Dae Jin Ha ◽  
Choongnyun Paul Kim ◽  
...  
Keyword(s):  
Injection Molding ◽  
Volume Fraction ◽  
Powder Injection Molding ◽  
Powder Injection

Effects of particle size and surface modification of SiC on the wear behavior of high volume fraction Al/SiCp composites

2020 ◽  
Vol 831 ◽  
pp. 154647 ◽  
Author(s):  
Taegyu Lee ◽  
Junho Lee ◽  
Donghyun Lee ◽  
Ilguk Jo ◽  
Sang Kwan Lee ◽  
...  
Keyword(s):  
Particle Size ◽  
Surface Modification ◽  
Volume Fraction ◽  
Wear Behavior ◽  
High Volume ◽  
High Volume Fraction

scholarly journals Structure and Properties of Co-Cr-Mo Alloy Manufactured by Powder Injection Molding Method

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2010
Author(s):  
Grzegorz Matula ◽  
Aleksandra Szatkowska ◽  
Krzysztof Matus ◽  
Błażej Tomiczek ◽  
Mirosława Pawlyta
Keyword(s):  
Low Temperature ◽  
Injection Molding ◽  
Bending Strength ◽  
Ceramic Powder ◽  
Ethylene Vinyl Acetate ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Cobalt Chromium ◽  
Molding Method ◽  
Cobalt Chromium Molybdenum

Cobalt–chromium–molybdenum alloys samples were obtained by the powder injection molding method (PIM). PIM is dedicated to the mass production of components and can manufacture several grades of dental screws, bolts, stabilizers, or implants. As a skeleton component, ethylene–vinyl acetate (EVA copolymer) with a low temperature of processing and softening point was used. The choice of a low-temperature binder made it necessary to use a coarse ceramic powder as a mechanical support of the green sample during sintering. The injection-molded materials were thermally degraded in N2 or Ar-5%H2 and further sintered in N2-5%H2 or Ar-5%H2 at 1300 or 1350 °C for 30 min. The structure of the obtained samples was characterized by X-ray diffraction and electron microscopy. Mechanical properties, including hardness and three-point bending tests, confirmed that a nitrogen-rich atmosphere significantly increases the bending strength compared to the material manufactured in Ar-5%H2. This is due to the precipitation of numerous fine nitrides and intermetallic phases that strengthen the ductile γ-phase matrix.

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