Effects of Mechanical Alloying on Microstructure and Properties of Powder Injection Moulded SiCp-Reinforced Aluminium Composite

2014 ◽  
Vol 597 ◽  
pp. 103-108
Author(s):  
Tapany Patcharawit ◽  
Suthin Klahan ◽  
Patcharee Rupkrathok ◽  
Nutthita Chuankrerkkul
Keyword(s):  
Mechanical Alloying ◽  
Sintering Temperature ◽  
Powder Injection ◽  
Solid Loading ◽  
Aluminium Composite ◽  
Attrition Mill ◽  
Aluminium Powder ◽  
Powder Injection Moulding ◽  
Two Phases ◽  
Feedstock Preparation

This research investigated effects of mechanical alloying on microstructure and hardness of 30 vol.% SiCp - reinforced aluminium composites produced by powder injection moulding. Mechanical alloying was performed via an attrition mill prior to feedstock preparation at 52% and 55% solid loadings. Powder injection molding was operated at 170 oC followed by debinding and sintering at 680-740 oC. Experimental results showed that mechanical alloying aided better mixing of aluminium powder and SiCp such that certain amounts of SiCp was observed to be engulfed into deformable aluminium powder matrix. This in turn increased the interfaces between the two phases, thus facilitating sintering of the composite. By employing mechanical alloying, the effective sintering temperature has significantly reduced from 740 oC down to 700 oC. Improved sintered density and hardness were obtained by increasing % solid loading and sintering temperature.

scholarly journals Liquid-Phase Sintering and Properties of PIMed 10-20 vol.% SiCp-Reinforced Aluminium Composites

2018 ◽  
Vol 237 ◽  
pp. 02015
Author(s):  
Tapany Patcharawit ◽  
Arada Ngeekoh ◽  
Usanee Kitkhamthorn ◽  
Nutthita Chuankrekkul
Keyword(s):  
Liquid Phase ◽  
Linear Shrinkage ◽  
Nitrogen Atmosphere ◽  
Liquid Phase Sintering ◽  
Age Hardening ◽  
Experimental Result ◽  
Powder Injection ◽  
Solid Loading ◽  
Aluminium Composite ◽  
Aluminium Powder

Liquid-phase sintering and properties of powder injection moulded aluminium composite reinforced with SiCp has been investigated via thermal-phase analyses and hardness property. Mixing of 10 and 20 vol.% SiCp and aluminium powder was done via ball milling prior to feedstock preparation at 55% solid loading. Powder injection moulding was carried out at 170°C, followed by solvent and thermal debinding. The brown samples were sintered in a nitrogen atmosphere at 650–660°C, prior to age-hardening. Experimental result shows relatively high % linear shrinkage of 9.9–21.9 % and high % volumetric shrinkage of 34.5–46.5%. Thermal analysis indicates the formation of the liquid around 632 °C, facilitating liquid phase sintering. The composite microstructures consists of uniformly distributed SiCp throughout the densified aluminium matrix. SiCp addition scales up SiCp clustering, accompanying with gap porosity. The composite reinforced with 10 vol.% SiCp possesses higher sintered density at 2.63 g/cm3, yielding 93.1% theoretical. However the maximum macro Vickers hardness was measured at 164.2 Hv for 20 vol.% SiCp – reinforced aluminium composite in the age-hardened condition. Liquid phase sintering was found effective for the microstructure evolution of the PIMed composite, rendering densification. Hardening is influenced by SiCp addition and the roles of AlN, Al2Cu and Mg2Si precipitates.

Fabrication of Injection Moulded 304L Stainless Steels Reinforced with Tungsten Carbide Particles

2012 ◽  
Vol 706-709 ◽  
pp. 638-642 ◽  
Author(s):  
Nutthita Chuankrerkkul ◽  
Parinya Chakartnarodom
Keyword(s):  
Tungsten Carbide ◽  
Sintering Temperature ◽  
Hydrogen Atmosphere ◽  
Powder Injection ◽  
304L Stainless Steel ◽  
Water Leaching ◽  
Powder Injection Moulding ◽  
Average Size ◽  
A Minor ◽  
Carbide Particles

Powder injection moulding of 304L stainless steel - tungsten carbide (WC) composites were carried out in the present work. Two different WC particle i.e. WC having average size of 4.8 µm and 1.6 µm were used. Feedstock of powder loading up to 55 vol% were successfully prepared using binder composed mainly of polyethylene glycol (PEG) and a minor constituent of polymethylmethacrylate (PMMA). The mouldings were leached in water at temperatures of 40 °C and 60 °C from 30 minutes to 24 hours in order to study the effect of leaching conditions on the removal of the PEG. The remaining binder, PMMA, provided strength to the mouldings after leaching of the PEG and it could be removed by pyrolysis during ramping up to the sintering temperature. Specimens were sintered under hydrogen atmosphere at 1250 °C for 1 hour. Sintered components were subjected to testing and characterisation. Scanning electron microscope was used to observe microstructure of specimens after moulding, leaching and sintering. It was found that the hardness of the sintered specimens increased with either increasing the amount of the powder loading in the feedstock or reducing the average size of WC in the powder mixture. In addition, the water leaching of the PEG linearly correlates with the natural log of time and the equation predicts that PEG will be removed completely in 11.24 ± 1.31 hours which corresponds with the experiment result that PEG completely removed in 12 hours.

Powder Injection Moulding and Liquid Phase Sintering of Aluminium - SiC Particulate Composite

2021 ◽  
Vol 904 ◽  
pp. 213-220
Author(s):  
Tapany Patcharawit ◽  
Phongsathon Thongbo ◽  
Nitithorn Sengna ◽  
Piyanat Auttachon ◽  
Nutthita Chuankrerkkul
Keyword(s):  
Injection Moulding ◽  
Particulate Composite ◽  
Liquid Phase Sintering ◽  
Powder Injection ◽  
Solid Loading ◽  
Powder Injection Moulding ◽  
Mould Filling ◽  
Commercial Aluminium ◽  
Property Assessment ◽  
Microstructure Density

Metal matrix composite has been increasingly appreciated by many engineering applications due it its tailored properties for specific uses. Powder injection moulding is one of the most effective composite processing essentially for small and complex parts. Moulding of feedstock is the key step determining green and sintered properties. This research investigated effects of moulding parameters which are % solid loading and moulding speed on microstructure and properties of aluminium composite. Commercial aluminium alloy powder and SiC particulate at 15 vol.% addition were formulated at 55 % and 60 % solid loading. Injection moulding were operated using a horizontal screw driven typed machine at 1600-1800 rpm speed and 280 - 300 °C moulding temperature. After sintering at 655 °C, property assessment via microstructure, density, % shrinkage, distortion and hardness were carried out. It was found that feedstock of 55 % solid loading occasionally led to flash problem while that of higher solid loading experienced higher viscosity to fulfill four-cavity mould. Moulding speed investigated did not significantly affect mould filling and overall properties. Sintered microstructures generally showed well-distributed SiC particulate in the aluminium matrix. The optimum injection moulding condition was the feedstock prepared at 60% solid loading, moulding at 1800 rpm speed, which offered theoretical density of greater than 98.5 % and micro Vickers hardness of 125.2 Hv.

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.

Powder Injection Moulding of Alumina Using PEG/PVB Binder Systems

2013 ◽  
Vol 545 ◽  
pp. 173-176 ◽  
Author(s):  
Nutthita Chuankrerkkul ◽  
Pat Sooksaen ◽  
Piyawan Pakunthod ◽  
Tutiyachan Kosalwit ◽  
Wanwara Pinthong
Keyword(s):  
Injection Moulding ◽  
Removal Rate ◽  
Minor Component ◽  
Polyvinyl Butyral ◽  
Major Constituent ◽  
Powder Injection ◽  
Alumina Powder ◽  
Water Leaching ◽  
Powder Injection Moulding ◽  
Feedstock Preparation

Powder injection moulding (PIM) is a process that is suitable for a fabrication of small and complex shape components. It consists of 4 main steps: feedstock preparation by mixing powder and binder, injection moulding of the prepared feedstock into the desired mould, removal of the binder and finally sintering to obtain materials with specific properties. In this study, powder injection moulding of alumina (Al2O3), using polyethylene glycol (PEG) based binder systems, was investigated. PEG is soluble in water; therefore, the use of organic solvents required for debinding of wax-based binder system can be avoided. PEG with a molecular weight of either 1500 or 4000 was used as a major constituent together with polyvinyl butyral (PVB) as a minor component. Stearic acid was also added during feedstock preparation to act as a lubricant. After mixing the powder with the binder, a variety of Al2O3 feedstocks were injected into the moulds. The mouldings were prepared by a laboratory-scaled plunger-typed machine. Debinding was carried out using a combination of solvent extraction and thermal debinding. Water leaching tests were performed at 30 and 50 °C to study PEGs removal rate. The pyrolysis of PVB was completed during ramping up of the mouldings to the sintering temperature. The mouldings were subjected to sintering at 1500 °C in air. It was found from the study that PEG/PVB binder systems can be used for the preparation of alumina powder injection moulding feedstocks. Specimens retained their shapes during and after leaching of the PEGs.

Mechanical Properties of As-Exposed Al-SiCp Composite Fabricated by Powder Injection Moulding

2017 ◽  
Vol 751 ◽  
pp. 60-69 ◽  
Author(s):  
Tapany Patcharawit ◽  
Arada Ngeekoa ◽  
Wanphen Tongkerd ◽  
Sutam Takhampom ◽  
Supitcha Lapkeaw ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Injection Moulding ◽  
Solution Treatment ◽  
Tensile Failure ◽  
Powder Injection ◽  
Mechanical Degradation ◽  
Aluminium Composite ◽  
Powder Injection Moulding ◽  
Exposure Temperature ◽  
Short Term Exposure

This research investigated mechanical degradation of powder injection moulded SiCp-reinforced aluminium composite subjected to moderate temperature exposures. Aluminium composite of 20 vol.% SiCp reinforcement was produced by powder injection moulding and sintering at 680°C, followed by 500°C solution treatment plus 150°C for 6 hours artificial aging, and subsequent exposures at 100, 200 and 300°C for 10 and 100 hours. It was found that short-term exposure for 10 hours provided increasing hardness with increasing exposure temperature, while long-term exposure for 100 hours led to an opposite result. The maximum micro Vickers hardness was obtained at 182.2 Hv for Al-SiCp composite exposed at 300°C for 10 hours. Tensile strength was however found deleterious with increasing both exposure temperature and time. The maximum tensile strength was achieved at 191.2 MPa for Al-SiCp composite exposed at 100°C for 100 hours. The formations of AlN, Mg2Si and Al2Cu were observed in both age-hardened and as-exposed conditions. Furthermore, the highest temperature exposure at 300°C and extended exposure time at 100 hours resulted in the lowest hardness and tensile properties due possibly to the loss of coherency of precipitates. SiCp clusters were the main cause of the tensile failure.

scholarly journals Recent advances in PIM technology I

2008 ◽  
Vol 40 (1) ◽  
pp. 79-88 ◽  
Author(s):  
B.S. Zlatkov ◽  
E. Griesmayer ◽  
H. Loibl ◽  
O.S. Aleksic ◽  
H. Danninger ◽  
...  
Keyword(s):  
Injection Moulding ◽  
Flow Diagram ◽  
Powder Injection ◽  
Main Process ◽  
Metal Parts ◽  
Surface Active Agents ◽  
Powder Injection Moulding ◽  
Powder Characteristics ◽  
Feedstock Preparation ◽  
Stainless Steel 316

In this article the state of art of the PIM (Powder Injection Moulding) technology is given in brief. The main process flow diagram consisting of four steps: feedstock preparation, injection moulding (green samples forming), the debinding (binder removing) procedure and the sintering process was described. After that the materials for binders and additives for the surface active agents were mentioned in brief. The metal injection moulding (MIM) process was analysed in more detail: MIM- stainless steels, MIM-copper and MIM-aluminium as the most metals common in MIM metal parts production. After that our results of MIM stainless steel 316 L and MIM copper are given. The main powder characteristics, the shrinkage and density of the sintered samples were compared for isostatically pressed PM (powder metallurgy) samples and MIM formed samples. The SEM fractographs of MIM and PM samples are given for MIM green parts, debinded (brown) parts and sintered parts, and PM green parts and sintered parts. The results obtained were compared with literature data before they were applied in metal parts production.

scholarly journals Recent advances in PIM technology I

2008 ◽  
Vol 40 (1) ◽  
pp. 79-88
Author(s):  
B.S. Zlatkov ◽  
E. Griesmayer ◽  
H. Loibl ◽  
O.S. Aleksic ◽  
H. Danninger ◽  
...  
Keyword(s):  
Injection Moulding ◽  
Flow Diagram ◽  
Powder Injection ◽  
Main Process ◽  
Metal Parts ◽  
Surface Active Agents ◽  
Powder Injection Moulding ◽  
Powder Characteristics ◽  
Feedstock Preparation ◽  
Stainless Steel 316

In this article the state of art of the PIM (Powder Injection Moulding) technology is given in brief. The main process flow diagram consisting of four steps: feedstock preparation, injection moulding (green samples forming), the debinding (binder removing) procedure and the sintering process was described. After that the materials for binders and additives for the surface active agents were mentioned in brief. The metal injection moulding (MIM) process was analysed in more detail: MIM- stainless steels, MIM-copper and MIM-aluminium as the most metals common in MIM metal parts production. After that our results of MIM stainless steel 316 L and MIM copper are given. The main powder characteristics, the shrinkage and density of the sintered samples were compared for isostatically pressed PM (powder metallurgy) samples and MIM formed samples. The SEM fractographs of MIM and PM samples are given for MIM green parts, debinded (brown) parts and sintered parts, and PM green parts and sintered parts. The results obtained were compared with literature data before they were applied in metal parts production.

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