| 학회 | 한국재료학회 |
| 학술대회 | 2004년 가을 (11/05 ~ 11/05, 인하대학교) |
| 권호 | 10권 2호 |
| 발표분야 | 금속 |
| 제목 | Co-Cr-Mo 임플런트 합금 분말의 소결에 따른 미세조직 |
| 초록 | 1. Introduction Recently, rapid advancement of biomedical technology has led to the widespread development of various bioengineering materials. Among these materials, Co-Cr-Mo based implant alloys are getting significant attention as one of the most attractive orthopedic implant materials due to their unique attributes which include excellent biocompatibility in the human environment, high corrosion resistance and good mechanical strength[3]. Alternatively, there is very limited information on powder metallurgy processing methods such as hot isostatic pressing(HIP) for the processing and manufacturing of orthopedic devices using cobalt alloys. In contrast, there are numerous publications available for the processing and production of cast and wrought Co alloys. Accordingly, the aim of this work is to investigate the effect of sintering on the exhibited Co microstructures and properties. 2. Experimental A commercial Co-Cr-Mo based alloy powder, with a particle size of -100+325M, was used in present study. The chemical composition of this powder is given in Table 1. For each green compact, 300g of alloy powder were mixed with a paraffin-dissolved benzene solution, and then heated up to 70℃ to allow complete benzene evaporation. The powder containing the paraffin was compacted into a cylindrical high strength steel mold of 25㎜ in diameter by 10㎜ in height, under a pressure of 5 ton/㎠. The implemented heat treatment consisted of two different thermal cycles for compact sintering single compacts were heated to 450℃ and held at this temperature for 1 hour under a vacuum of 10-2 Torr to allow all the paraffin to be evaporated. Later on, each paraffin-free powder compact was sintered at eight different temperatures, ranging from 950℃ to 1300℃, for various time periods under vacuum. The density of the sintered specimens was measured using the Archimedes method. In addition, hardness measurements were made on specimens cut perpendicular to the main axis of the cylindrical mold, using the Rockwell C-scale hardness(HRC). 3. Results and Discussion Notice that the density of the sintered specimen increases linearly as the sintering temperature increases. The HRC values gradually decrease with increasing temperatures of up to 1150℃. Sintering at higher temperatures does not lead to further drops in the compact hardness. The decrease in hardness with temperature (up to 1150℃) is attributed to grain growth within the powder particle. The observed microstructures indicate that there is a distribution of fine pores along the grain boundaries and even in grains within particles for both specimens. The amount of porosity seems to decrease for the specimen sintered at 1200℃ when compared with that sintered at 1050℃. Since hardness is intimately related to grain size in an inverse way, the hardness measured in the sintered specimen at the relative low temperature was expected to be higher than that corresponding to the sintered specimen at high temperature. |
| 저자 | 박헌범1, 송창빈1, 성환구2, H. F. Lpez2 |
| 소속 | 1공주대, 2Univ. of Wisconsin-Milwaukee |
| 키워드 | 코발트; 크롬; 몰리브덴; 합금분말; 소결; 생체재료 |
