• Title, Summary, Keyword: Metal Powder

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Production of Ni-Cr Metal Powder by Selective Laser Melting for Dentistry to Observation of Characteristics (치과 SLM용 Ni-Cr 금속분말 특성 관찰)

  • Hong, Minho
    • The Journal of Korean Academy of Dental Technology
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    • v.37 no.1
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    • pp.23-29
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    • 2015
  • Purpose: The selective laser melting (SLM) process for dentistry, which is one of the additive manufacturing technologies (AM) allows for rapid production of a three-dimensional model with complex shape by directly melting metal powder. This process generates detailed items of a three-dimensional model shape through consolidation of a thin powder layer by utilizing both selective melting and laser beam simultaneously. In regard to SLM process, Fe-base powder, Ti-6AI-4V powder, AI-base powder, etc. have been researched. It is believed that the aforementioned technologies will be widely utilized in manufacturing metal parts using metal powder of raw material. This study chose Ni-Cr-Mo metal powder in order to manufacture metal powder materials that would be used in the selective laser melting for dentistry. Methods: This study manufactured metal powder using mechanical alloying technique (MA) among those metal powder manufacturing techniques. Moreover, this study aimed to utilize the metal powder manufactured after observing the characteristics of powder as preliminary data of Ni-Cr-Mo metal powder. This study could obtain the following conclusions within the experimental limitations. Results: As a result of mechanically alloying Ni-Cr-Mo powder over time, its mean particle size was $66.93{\mu}m$ $54.4{\mu}m$ and $45.39{\mu}m$ at 10h, 20h and 30h, respectively. The gtain form of metal powder by mechanical alloying technique was a sponge-like shape of irregular plate; however, the gtain form manufactured by high-pressure water aromization process had the following three types: globular type, chain type and oval type. Conclusion: This study found $37.65{\mu}m$ as the mean particle size of Ni-Cr-Mo metal powder, which was manufactured using water atomization technique under the following conditions: water atomization flux of 300 liter/min, hydraulic pressure of $400kgf/cm^2$ and injection angle of $45^{\circ}$. This study confirmed that the grain form of powder (solid particle form) would vary depending on the manufacturing process.

Dissolution Phenomenon of the Base Metal during TLP Bonding Using the Modified Base Metal Powder and Ni Base Filler Metal Powder (유사 조성의 모재분말과 Ni기 삽입금속 혼합분말을 사용한 천이액상확산 접합 시 모재의 용해현상)

  • Song, Woo-Young;Ye, Chang-Ho;Kang, Chung-Yun
    • Journal of Welding and Joining
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    • v.25 no.3
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    • pp.64-71
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    • 2007
  • The dissolution phenomenon of the solid phase powder and base metal by liquid phase insert metal during Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111(base metal) powder and the GNi3 (Ni-l4Cr-9.5Co-3.5Al-2.5B) powder was investigated. In case of the mixed powder contains modified GTD111 powder 50wt%, all of the powder was melted by liquid phase at 1423K. At the temperature between solidus and liquidus of GNi3, liquid phase penetrated into the boundary of the modified GTD111 powder and solid particle separated from powder was melted easily because area of reaction was increased. With increasing mixing ratio of the modified GTD111, it needed the higher temperature to melt all of the modified GTD111 powder. During Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111 50wt% and GNi3 50wt% as insert metal, width of the bonded interlayer was increased with increasing bonding temperature by reaction of the base metal and liquid phase in insert metal. Dissolution of the base metal and modified powder by liquid phase progressed all together and after all of the powder was melted nearly, the dissolution of the base metal occurred quickly.

The Mixing Ratio Effect of Insert Metal Powder and Insert Brazing Powder on Microstructure of the Region Brazed on DS Ni Base Super Alloy (일방향응고 Ni기 초내열합금 천이액상화산접합부의 미세조직에 미치는 모재와 삽입금속 분말 혼합비의 영향)

  • Ye Chang-Ho;Lee Bong-Keun;Song Woo-Young;Oh In-Seok;Kang Chung-Yun
    • Journal of Welding and Joining
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    • v.23 no.6
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    • pp.99-105
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    • 2005
  • The mixing ratio effect of the GTD-111(base metal) powder and the GNI-3 (Ni-l4Cr-9.5Co-3.5Al-2.5B) powder on TLP(Transient Liquid Phase) bonding phenomena and mechanism was investigated. At the mixing ratio of the base metal powder under $50wt\%$, the base metal powders fully melted at the initial time and a large amount of the base metal near the bonded interlayer was dissolved by liquid inter metal. Liquid insert metal was eliminated by isothermal solidification which was controlled by the diffusion of B into the base metal. The solid phases in the bonded interlayer grew epitaxially from the base metal near the bonded interlayer inward the insert metal during the isothermal solidification. The number of grain boundaries farmed at the bonded interlayer corresponded with those of base metal. At the mixing ratio above $60wt\%$, the base metal powder melted only at the surface of the powder and the amount of the base metal dissolution was also less at the initial time. Nuclear of solids firmed not only from the base metal near the bonded interlayer but also from the remained base metal powder in the bonded interlayer. Finally, the polycrystal in the bonded interlayer was formed when the isothermal solidification finished. When the isothermal solidification was finished, the contents of the elements in the boned interlayer were approximately equal to those of the base metal. Cr-W borides and Cr-W-Ta-Ti borides formed in the base metal near the bonded interlayer. And these borides decreased with the increasing of holding time.

Densification Behavior of Metal and Ceramic Powder under Cold Compaction

  • Lee, Sung-Chul;Kim, Ki-Tae
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.179-180
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    • 2006
  • Densification behavior of various metal and ceramic powder was investigated under cold compaction. The Cap model was proposed based on the parameters obtained from axial and radial deformation of sintered metal powder compacts under uniaxial compression and volumetric strain evolution. For ceramic powder, the parameters were obtained from deformation of green powder compacts under triaxial compression. The Cap model was implemented into a finite element program (ABAQUS) to compare with experimental data for densification behavior of various metal and ceramic powder under cold compaction.

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The Bonding Strength Characteristic of the Filler Metal Powder on the TLP Bonded Region of Superalloy GTD-111DS (일방향 초내열합금 GTD-111DS에서 삽입금속 분말에 따른 천이액상확산접합부의 접합강도 특성)

  • Oh, In-Seok;Kim, Gil-Moo;Moon, Byeong-Shik
    • Journal of Welding and Joining
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    • v.25 no.5
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    • pp.45-50
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    • 2007
  • The Ni-base superalloy GTD111 DS is used in the first stage blade of high power land-based gas turbines. Advanced repair technologies of the blade have been introduced to the gas turbine industry over recent years. The effect of the filler metal powder on Transient Liquid Phase bonding phenomenon and tensile mechanical properties was investigated on the GTD111 DS superalloy. At the filler metal powder N series, the base metal powders fully melted at the initial time and a large amount of the base metal near the bonded interlayer was dissolved by liquid inter metal. Liquid filler metal powder was eliminated by isothermal solidification which was controlled by the diffusion of B into the base metal. The solids in the bonded interlayer grew from the base metal near the bonded interlayer inward the insert metal during the isothermal solidification. The bond strength of N series filler metal powder was over 1000 MPa. and ${\gamma}'$ phase size of N series TLP bonded region was similar with base metal by influence of Ti, Al elements. At the insert metal powder M series, the Si element fluidity of the filler metal was good but microstructure irregularity on bonded region because of excessive Si element. Nuclear of solids formed not only from the base metal near the bonded interlayer but also from the remained filler metal powder in the bonded interlayer. When the isothermal solidification was finished, the content of the elements in the boned interlayer was approximately equal to that of the base metal. But boride and silicide formed in the base metal near the bonded interlayer. And these boride decreased with the increasing of holding time. The bond strength of M series filler metal powder was about 400 MPa.

Densification behavior of metal powder under warm isostaic pessing with metal mold (금속 몰드를 이용한 금속 분말의 온간 등가압 성형)

  • Park, Jung-Goo;Kim, Ki-Tae
    • Proceedings of the KSME Conference
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    • pp.1352-1357
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    • 2003
  • The effect of the metal mold on densification behavior of stainless steel 316L powder was investigated under warm isostatic pressing with metal mold. We use lead as metal mold and obtain experimental data of metal mold property. To simulate densification of metal powder, the elastoplastic constitutive equation proposed by Shima and Oyane was implemented into a finite element program (ABAQUS) under warm die pressing and warm isostatic pressing with metal mold. Finite element results were compared with experimental data for densification and deformation of metal powder under warm isostatic pressing and warm die pressing.

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Densification Behavior of Metal Powder Under Warm Isostatic Pressing with a Metal Mold (금속 몰드를 이용한 금속 분말의 온간 등가압 성형)

  • Park, Jung-Goo;Kim, Ki-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.6
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    • pp.838-847
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    • 2004
  • The effect of a metal mold on densification behavior of stainless steel 316L powder was investigated under warm isostatic pressing with a metal mold. We use lead as a metal mold and obtain experimental data of metal mold properties. To simulate densification behavior of metal powder, elastoplastic constitutive equation proposed by Shima and Oyane was implemented into a finite element program (ABAQUS) under warm die pressing and warm isostatic pressing with a metal mold. Finite element results were compared with experimental data for densification and deformation of metal powder under warm isostatic pressing and warm die pressing.

Synthesis of Boron Nitride Nanotubes via inductively Coupled thermal Plasma process Catalyzed by Solid-state ammonium Chloride

  • Chang, Mi Se;Nam, Young Gyun;Yang, Sangsun;Kim, Kyung Tae;Yu, Ji Hun;Kim, Yong-Jin;Jeong, Jae Won
    • Journal of Korean Powder Metallurgy Institute
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    • v.25 no.2
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    • pp.120-125
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    • 2018
  • Boron nitride nanotubes (BNNTs) are receiving great attention because of their unusual material properties, such as high thermal conductivity, mechanical strength, and electrical resistance. However, high-throughput and high-efficiency synthesis of BNNTs has been hindered due to the high boiling point of boron (${\sim}4000^{\circ}C$) and weak interaction between boron and nitrogen. Although, hydrogen-catalyzed plasma synthesis has shown potential for scalable synthesis of BNNTs, the direct use of $H_2$ gas as a precursor material is not strongly recommended, as it is extremely flammable. In the present study, BNNTs have been synthesized using radio-frequency inductively coupled thermal plasma (RF-ITP) catalyzed by solid-state ammonium chloride ($NH_4Cl$), a safe catalyst materials for BNNT synthesis. Similar to BNNTs synthesized from h-BN (hexagonal boron nitride) + $H_2$, successful fabrication of BNNTs synthesized from $h-BN+NH_4Cl$ is confirmed by their sheet-like properties, FE-SEM images, and XRD analysis. In addition, improved dispersion properties in aqueous solution are found in BNNTs synthesized from $h-BN+NH_4Cl$.

Net-shape Manufacturing of Micro Porous Metal Components by Powder Injection Molding

  • Nishiyabu, Kazuaki;Matsuzaki, Satoru;Tanaka, Shigeo
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.93-94
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    • 2006
  • A novel production method for porous metal components has been developed by applying powder space holder (PSH) method to metal powder injection molding (MIM) process. The PSH-MIM method has an industrial competitive advantage that is capable of net-shape manufacturing the micro-sized porous metal products with complicated shapes and controlled porosity and pore size. In this study, the small impeller with homogeneous micro-porous structure was manufactured by the PSH-MIM method. The effects of combinations in size and fraction of PMMA particle on dimensional tolerance and variation of sintered porous specimens were investigated. It was concluded that the PSH-MIM method could manufacture commercially microporous metal components with high dimensional accuracy.

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A Study on Pore Properties of SUS316L Powder Porous Metal Fabricated by Electrostatic Powder Coating Process (정전분체코팅 공정으로 제조된 SUS316L 분말 다공체의 기공 특성에 관한 연구)

  • Lee, Min-Jeong;Yi, Yu-Jeong;Kim, Hyeon-Ju;Park, Manho;Kim, Byoung-Kee;Yun, Jung-Yeul
    • Journal of Korean Powder Metallurgy Institute
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    • v.25 no.5
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    • pp.415-419
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    • 2018
  • Porous metals demonstrate not only excessively low densities, but also novel physical, thermal, mechanical, electrical, and acoustic properties. Thus, porous metals exhibit exceptional performance, which are useful for diesel particulate filters, heat exchangers, and noise absorbers. In this study, SUS316L foam with 90% porosity and $3,000{\mu}m$ pore size is successfully manufactured using the electrostatic powder coating (ESPC) process. The mean size of SUS316L powders is approximately $12.33{\mu}m$. The pore properties are evaluated using SEM and Archimedes. As the quantity of powder coating increases, pore size decreases from 2,881 to $1,356{\mu}m$. Moreover, the strut thickness and apparent density increase from 423.7 to $898.3{\mu}m$ and from 0.278 to $0.840g/cm^3$, respectively. It demonstrates that pore properties of SUS316L powder porous metal are controllable by template type and quantity of powder coating.