간행물
한국분말야금학회지 KCI 등재 Journal of Korean Powder Metallurgy Institute
- 발행기관 한국분말재료학회(구 한국분말야금학회)
- 자료유형 학술지
- 간기 격월간
- ISSN 1225-7591 (Print)2287-8173 (Online)
- 수록기간 1994 ~ 2024
- 주제분류 공학 > 금속공학 공학 분류의 다른 간행물
- 십진분류KDC 559DDC 629
권호리스트/논문검색
Vol. 3 No. 2 (1996년 6월) 7건
1.
1996.06
구독 인증기관 무료, 개인회원 유료
4,000원
2.
1996.06
구독 인증기관 무료, 개인회원 유료
Effects of the Addition of Other Carbides on the Properties of Submicron WC-10% Co Cemented Carbides
The effects of added VC, CrC and TaC on the microstructures and properties of submicron WC-10%Co cemented carbides. The relative sintered density of compact was increased by addition of CrC but decreased oppositely by addition of VC or TaC. The growth of WC grains was significantly suppressed by addition of these carbides. The hardness of these alloys was increased by addition of other carbides and showed a maximum value by simultaneously added VC and CrC. The transverse rupture strength(T.R.S.) was in- creased by addition of CrC, while it was decreased by addition of VC or TaC. The relative sintered density and T.R.S. of these alloys were improved by HIP-treatment. The maximum T.R.S. was 328kg/mm in the Wc-10%Co cemented carbide with addition of 0.5%VC.
4,000원
3.
1996.06
구독 인증기관 무료, 개인회원 유료
The effect of vacuum annealing on the oxidation behavior of milled WC-15%Co powder mixture has been studied. A cobalt component in the milled powder mixture was oxidized preferentially above 175 in air. The specimens showed a steady increase in weight at 175 but did constant weight followed by rapid increase in specimen weight at the beginning above 20. Oxidation of the milled powder mixture was significantly suppressed by vacuum annealing at 30 for 10 h. Suppression of oxidation by vacuum annealing and different oxidation behaviors of the milled powder mixture between 175 and 20, were attributed to removal of strain energy stored in the cobalt powder during vacuum annealing or oxidation treatment above 20. The role of stored strain energy on oxidation of milled WC-15%Co powder mixture was proved by X-ray diffraction method and differential thermal analysis.
4,000원
4.
1996.06
구독 인증기관 무료, 개인회원 유료
The densification of the compacts of pure Co, Fe+50%.Co and Fe+25% Co sintered under H gas or in vacuum was investigated. The effects of AL, Nb, Ti, and V additions on the densification were also studied. The sintered compact of Co was fully-dense when the density of the compact was lower than . However, above , it was never fully-dense regardless of sintering atmosphere, temperature, and time. The densification of sintered compacts of Fe-50% Co and Fe-25% Co were always incomplete. While the addition of AL made all compacts fully-dense, the addition of Ti was effective for the compacts of Co and Fe-25% Co. V was effective only for the Fe-25% Co. These results tell us that the particle size of Co powder, the amount of Fe, and the amount of additives forming stable oxides play on important role for the complete densification. Therefore it is desirable to reduce or eliminate the equilibrium pressure of HO or CO in isolated pores to obtain a fully-dense sintered compact.
4,000원
5.
1996.06
구독 인증기관 무료, 개인회원 유료
In order to obtain homogeneous and high quality products in powder compaction forging process, it is very important to control stress, strain, density and density distributions. Therefore, it is necessary to understand quantitatively the elasto-plastic deformation and densification behaviors of porous metals and metal powders. In this study, elasto-plastic finite element method using Lee-Kim's pressure dependent porous material yield function has been used for the analysis of three dimensional indenting process. The analysis predicts deformed geometry, stress, strain and density distribution and load. The calculated load is in good agreement with experimental one. The calculated results do not show axisymmetric distributions because of the edge effect. The core part which is in contact with the indentor and the outer diagonal edge part are in compressive stress states and the middle part is in tensile stress state. As a results, it can be concluded that three dimensional analysis is more realistic than axisymmetric assumption approach.
4,000원
6.
1996.06
구독 인증기관 무료, 개인회원 유료
Using rice husks pulverized by rotating knife cutter, the raw rice husk powder was solution treated by nitric and hydrochloric acids in order to separate phytolith from organic constituents. Because of the strong resistance of organic components of rice husk to acids, the raw powder had to be boiled in concentrated acids up to 300 min. By boiling in nitric acid for 60~120 min, all organic components were resolved while amorphous silica Powder of about 20 nm in size and of higher than 99.8% in purity was left behind. Inferior to the nitric acid, hydrochloric acid was not able to resolve organic component completely leaving unresolved matter of about 40% by weight even after 300 min of boiling. From the acid treatments and impurity analyses, it is considered that most of metallic elements in rice husks are combined to organic components that are easily soluble to acids.
4,000원
7.
1996.06
구독 인증기관 무료, 개인회원 유료
4,000원
