Powder Injection Molding of Cu-Based Amorphous Powders and Fe-Based Metamorphic Powders

2008 ◽  
Author(s):  
Chang-Young Son ◽  
Chang Kyu Kim ◽  
Dae Jin Ha ◽  
Tae Shik Yoon ◽  
Sunghak Lee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Injection Molding ◽  
Volume Fraction ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Austenitic Matrix ◽  
Amorphous Phases ◽  
Amorphous Powders ◽  
Injection Molded

Powder injection molding (PIM) process was applied to Cu-based amorphous alloy powders and Fe-based metamorphic alloy powders, and microstructure, hardness, and wear resistance of the PIM products were analyzed. When Cu-based amorphous powders were injection-molded and sintered at 470 °C, sintering was not made since most of amorphous phases were replaced by crystalline phases. When sintered at higher temperatures, volume fraction of pores inside the sintered specimens decreased, but sintering was not properly conducted. When Fe-based metamorphic powders were injection-molded and then sintered at 1200 °C, completely densified products with almost no pores were obtained. They contained 34 vol.% of (Cr, Fe)2B borides dispersed in the austenitic matrix without amorphous phases. Since these (Cr, Fe)2B borides were hard and thermally stable, hardness, high-temperature hardness, and wear resistance of the PIM products of Fe-based metamorphic powders were twice as high as those of conventional PIM stainless steel products. These findings suggested new applicability of the PIM products of Fe-based metamorphic powders to structures and parts requiring excellent mechanical properties.

Microstructure, Hardness, and Wear Resistance of Powder-Injection-Molded Products of Fe-Based Metamorphic Powders

2007 ◽  
Vol 26-28 ◽  
pp. 355-358
Author(s):  
Chang Kyu Kim ◽  
Chang Young Son ◽  
Dae Jin Ha ◽  
Tae Sik Yoon ◽  
Sung Hak Lee
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Wear Resistance ◽  
Injection Molding ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Thermally Stable ◽  
Austenitic Matrix ◽  
Amorphous Phases ◽  
Injection Molded

Powder injection molding (PIM) process was applied to Fe-based metamorphic alloy powders, and microstructure, hardness, and wear resistance of the PIM products were analyzed and compared with those of conventional PIM stainless steel products. When Fe-based metamorphic powders were injection-molded and then sintered at 1200 oC, completely densified products with almost no pores were obtained. They contained 34 vol.% of (Cr,Fe)2B borides dispersed in the austenitic matrix without amorphous phases. Since these (Cr,Fe)2B borides were very hard and thermally stable, hardness, and wear resistance of the PIM products of Fe-based metamorphic powders were twice as high as those of conventional PIM stainless steel products. Such property improvement suggested new applicability of the PIM products of Fe-based metamorphic powders to structures and parts requiring excellent mechanical properties.

Wear Resistance of Hard Coatings in Powder Injection Molding (PIM)

2010 ◽  
Author(s):  
Ali Keshavarz Panahi ◽  
Hossein Khoshkish ◽  
Mostafa Rezaee Saraji
Keyword(s):  
Wear Resistance ◽  
Injection Molding ◽  
Wear Behavior ◽  
Chemical Vapour ◽  
Powder Injection Molding ◽  
Economic Feasibility ◽  
Hard Coatings ◽  
Powder Injection ◽  
Good Opportunity ◽  
Wear Protection

The degree of machine wear decisively determines the economic feasibility of powder injection molding. According to higher hardness of alumina powders (ca. 2000HV), manufacturing of ceramic components via PIM requires hard wear resistance equipments to overcome the wear phenomena. The wear test is based on the ASTM rubber wheel but the rubber wheel is replaced by a steel wheel of the same grade used in the barrel of an injection molding machine. The potential of hard coatings for wear protection in feedstock processing units is investigated in the present study. Model wear tests were carried out to demonstrate the tribological situation inside the screw/barrel system of extruders and injection molding machines. The substrate material was AISI 4140 steel which is used for PIM machine components. Hard coatings prepared by physical vapor deposition (PVD) and chemical vapour deposition (CVD) offer a good opportunity for wear protection. Due to higher temperature of feedstock and compression, the amount of wear in the metering zone is higher in comparison with other zones. The wear behavior also was strongly influenced by the characteristics of the feedstock (e.g. amount, size, shape and hardness of ceramic particles).

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.

Powder Injection Molding of Niobium

2005 ◽  
Vol 475-479 ◽  
pp. 711-716 ◽  
Author(s):  
Ivi Smid ◽  
Gaurav Aggarwal
Keyword(s):  
High Temperature ◽  
Injection Molding ◽  
Specific Weight ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Rocket Engines ◽  
Low Oxygen ◽  
Pure Niobium ◽  
Sintering Time ◽  
Injection Molded

Niobium and niobium-based alloys are used in a variety of high temperature applications ranging from light bulbs to rocket engines. Niobium has excellent formability and the lowest specific weight among refractory metals (Nb, Ta, Mo, W, and Re). Powder injection molding of niobium powder was investigated for efficiency of the process. The sintering of injection molded bars was conducted up to 2000°C in vacuum and low oxygen partial pressure atmosphere. This paper investigates the effect of sintering time, temperature and atmosphere on processing of pure niobium.

Characterization of Feedstocks for Injection Molded SiCp-Reinforced Al-4.5 wt.%Cu Composite

2011 ◽  
Vol 383-390 ◽  
pp. 3234-3240 ◽  
Author(s):  
Tapany Udomphol ◽  
Benchawan Inpanya ◽  
Nutthita Chuankrerkkul
Keyword(s):  
Injection Molding ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Solid Loading ◽  
Aluminium Powder ◽  
Twin Screw ◽  
Injection Molded ◽  
Hardness Values ◽  
Potential Use

Characterization of feedstocks for powder injection molding of SiCp-reinforced aluminium composite, as potential use for automotive and light-weight applications, has been studied in this research. Al-4.5 wt.% Cu powder, SiCp and polymeric binder were pre-mixed and compounded using a twin screw extruder at 170oC prior to powder injection molding at 170 oC. Effects of varied solid loadings at 52, 55 and 58% on green properties of the feedstocks have been investigated. Experimental results showed that compounding followed by powder injection molding allowed uniform distribution of SiCp surrounding the aluminium powder. It was found that higher solid loading improved bulk density while hardness values were observed to be similar. Molded specimens of 55% solid loading provided the optimum bend strength and strain at failure. Moreover, it was observed that the opposing abrasive property with angular shape of SiCp resulted in SiCp scratching effect, leading to irregular surface of aluminium powder after injection molding. This consequence and molding porosity were expected to be responsible for relatively low density of the molded specimens, giving the difficulty in molding at higher solid loading.

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

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.

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