Effect of particle size and sintering temperature on densification during coupled multifield-activated microforming
- PDF / 538,318 Bytes
- 8 Pages / 584.957 x 782.986 pts Page_size
- 17 Downloads / 212 Views
in Department of Design, Manufacture and Engineering Management, Manufacturing Engineering Research Centre, The University of Strathclyde, Glasgow, G1 1XJ, United Kingdom
Gang Yang School of Manufacturing Science and Engineering, Sichuan University, Chengdu, Sichuan 610065, People’s Republic of China (Received 19 March 2012; accepted 16 July 2012)
In this paper, a novel sintering method is introduced for the forming of microcomponents in which the loose powders were loaded directly into the die, sintered with an external electric field, a thermal field, and an external stress field (called coupled multifields activation), where the fields were generated by a Gleeble thermal simulation instrument. Two kinds of 316L stainless steel powders of different particle sizes (20 and 70 lm) with no binder were sintered with microforming using a multifield coupling method. For particle size of 20 lm, a nearly fully densified microsintered compact (relative density is 99.2%) was manufactured at a relatively low sintering temperature (900 °C) and within a relatively short sintering time (4 min). The fluctuated temperature–time curve reveals that the rapid mass transfer of liquid phase is the dominant densification mechanism in the compacts with a starting particle size of 20 lm. I. INTRODUCTION
On the technology front, during last 10 years, manufacture of microcomponents and miniaturization of manufacturing equipment/devices have obtained notable development globally, which deal with the manufacturing at miniature (e.g., ,10 mm), micro (,1.0 mm), and submicro (0.1–1.0 lm) scale. Various manufacturing methods have been emerging to cover a wide range of materials and applications.1–3 Microsystem technology is one of the leading technologies of producing microcomponents ranging from nanometers to millimeters.4,5 X-ray lithography is a conventional microfabrication technique, which is suitable to fabricate polymeric and silicon-based materials.6,7 Other fabrication techniques, such as micro-electro-discharge machining (EDM) and laser micromachining provide a wide range of material microcomponents.8,9 EDM is limited to conductive materials and laser micromachining produces structures with rough edges. Electroforming is another microfabrication technique used for producing microcomponents from metallic materials.10,11 Electroforming has a difficulty in producing microcomponents with thickness higher than 0.5 mm. Micrometal injection molding is a technique developed from metal injection a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2012.262 J. Mater. Res., Vol. 27, No. 20, Oct 28, 2012
molding to fabricate microcomponents from wide range of materials,12–14 and the whole process includes mixing, injection molding, debinding, and sintering. Soft lithography is a new microfabrication technique emerging few years ago. It was successful in the production of freestanding micromachines parts from metallic as well as ceramic materials.15–18 However, these methods are either very expensive because of the re
Data Loading...
