In Situ ceramic particle-reinforced aluminum matrix composites fabricated by reaction pressing in the TiO 2 (Ti)-Al-B (B
- PDF / 3,111,385 Bytes
- 12 Pages / 612 x 792 pts (letter) Page_size
- 21 Downloads / 207 Views
I.
INTRODUCTION
ALUMINUM alloys discontinuously reinforced with ceramic particulates are currently being developed for various high-performance applications. SiC,[1–6] TiC,[5,6,7] B4C,[5,6,8] TiB2,[4–6,9] Si3N4,[10,11] and Al2O3[4,12,13] have been examined for their potential reinforcement applications in aluminum matrix composites. It is generally accepted that a reduction in the particle size of the reinforcement, as well as a strong mechanical bond at the interface without the presence of a chemical reaction product, would lead to an improvement in strength. To improve the interfacial compatibility and reduce the reinforcement size, various new processing techniques are being employed to fabricate the high-performance composites. A process termed the XD* technique[14] *XD is a trademark of Martin Marietta Corporation, Bethesda, MD.
has been developed to fabricate in situ ultrafine ceramic particle-reinforced metal matrix composites (MMCs). The basic principle of this technique is that the ultrafine ceramic particles are formed in situ by the exothermic reaction between elements or between the elements and the compounds. Using this approach, MMCs with a wide range of matrix materials (including aluminum, iron, copper, lead, nickel, and titanium) and second-phase particles (including borides, carbides, nitrides, oxides, and their mixtures) can be produced.[14–21] Among these reinforcing particles, titanium diboride (TiB2) is particularly attractive since it ex-
Z.Y. MA, Associate Scientist, is with the Institute of Metals Research, Chinese Academy of Science, Shenyang 110015, China. S.C. TJONG, Associate Professor, is with the Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong. Manuscript submitted August 13, 1996. METALLURGICAL AND MATERIALS TRANSACTIONS A
hibits high elastic modulus and hardness and high thermal conductivity.[22] The literature on in situ TiB2 particle composites is limited. Kuruvilla et al.[23] have fabricated the in situ TiB2 particulate-reinforced aluminum composite by hot pressing and reaction sintering Ti, Al, and B powders. They reported that TiB2 particulates with a size of about 1 mm were formed in situ in the aluminum matrix. In addition, there also existed some irregularly shaped Al3Ti particles (about 1 vol pct) with a size of several tens of micrometers in the in situ composite.[24] Compared to the conventional TiB2/Al composite, the in situ TiB2/Al composite exhibited much higher strength and modulus,[23] as well as significant improvement in creep resistance.[24] Recently, Ma and co-workers[25,26,27] reported preliminary results on the in situ fabrication of the aluminum matrix composites using Ti-Al-B and TiO2-AlB. They reported that in situ TiB2 particles are very effective in strengthening aluminum. In this work, we further investigate the microstructural aspects and mechanical properties of several in situ composites fabricated from TiO2 (Ti)-Al-B (B2O3). Furthermore, the effects of CuO and SiC addition on the microstructure and m
Data Loading...
