• 한국주조공학회지
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• 제37권4호
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• pp.115-122
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• 2017

The aim of this research is to evaluate the wear properties of (TiB+TiC) paticulate reinforced titanium matrix composites (TMCs) by in-situ synthesis. Different particle sizes (1500, $150{\mu}m$) and contents (0.94, 1.88 and 3.76 mass% for Ti, 1.98 and 3.96 mass% for the Ti6Al4V alloy) of boron carbide were added to pure titanium and to a Ti6Al4V alloy matrix during vacuum induction melting to provide 5, 10 and 20 vol.% (TiB+TiC) particulate reinforcement amounts. The wear behavior of the (TiB+TiC) particulate reinforced TMCs is described in detail with regard to the coefficient of friction, the hardness, and the degree of reinforcement fragmentation during sliding wear. The worn surfaces of each sliding wear condition are shown for the three types of wear studied here: transfer layer wear, particle cohesion wear and the development of abrasive areas. The fine reinforcements of TMCs were easily fragmented from the Ti matrix as compared to coarse reinforcements, and fragmented debris accelerated the decrease in the wear resistance.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1025-1025
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• 2006

• 대한금속재료학회지
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• 제48권8호
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• pp.780-789
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• 2010

The aim of this study is to evaluate the microstructure and tensile property of in-situ (TiB+TiC) particulate reinforced titanium matrix composites (TMCs) synthesized by the investment casting process. Boron carbide ($1,500{\mu}m$ and $150{\mu}m$) was added to the titanium matrix during vacuum induction melting, which can provide the in-situ reaction of $5Ti+B_4C{\rightarrow}4TiB+TiC$. 0.94, 1.88 and 3.76 wt% of $B_4C$ were added to the melt. The phases identification of the in-situ synthesized TMCs was examined using scanning electron microscopy, an X-ray diffractometer, an electron probe micro-analyzer and transmission electron microscopy. Tensile properties of TMCs were investigated in accordance with the reinforcement size and volume fraction. The improvement of tensile property of titanium matrix composites was caused by load transfer from the titanium matrix to the reinforcement and by grain refinement of titanium matrix and reinforcements.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1026-1029
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• 2006

Particulate reinforced titanium composites were produced by PM rout. Differents volumetric percentages of TiN reinforcements were used, 5,10,15 vol%. Samples were uniaxial pressed and vacuum sintered at differents temperatures between $1200-1300^{\circ}C$. Density, porosity, shrinkage, mechanical properties and microstructure were studied. Elastic properties and strength resistance were analysed by flexural strength and tension tests, and after the test, fractured samples were analysed too, obtaining a correlation between the fracture, interparticulated or intraparticulated, and the reinforcement addition.. Hardness and microhardness test were applied too, in order to complete the study about mechanical properties. In order to study wear resistance pin-on-disc test were used. In addition, the temperature influence, the reactivity between matrix and reinforcement, and the microstructures developed were observed by optical and electron microscopy.

• Composites Research
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• 제33권5호
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• pp.256-261
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• 2020

본 연구에서는 Al-Ti-C 반응계의 점화온도에 대해 고찰하고, 자전연소합성법 및 교반주조 공정을 통해 TiC/Mg 금속복합재료를 제조하여 미세조직 및 기계적 특성을 분석하였다. 0, 10, 20, 30 vol.% TiC 입자가 균일하게 분산된 Mg 복합재료를 제조하였고, 강화재의 양이 증가할수록 기지 대비 우수한 압축강도 및 내마모특성을 보였다. 이는 in-situ 자전연소합성법에 의해 결함이나 불순물 등의 오염이 적은 TiC/Mg 금속복합재료 제조로 기지에서 강화재로의 효과적인 하중 전달에 의한 것으로 판단된다.

• 소성∙가공
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• 제8권3호
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• pp.259-259
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• 1999

TiC ceramic particulate-reinforced titanium matrix composites were fabricated and the resultant densification, microstructure, and static and dynamic mechanical properties were studied. Comparing Ti with TiH₂powders as host materials for TiC ceramic reinforcement by pressureless vacuum sintering, TiH₂-started composites showed better sinterability and resistance to both elastic and plastic deformation than Ti-started ones. When TiH₂and TiH₂-45 vol.%TiC samples were hot pressed, TiH₂matrices transformed to alpha prime Ti and alpha Ti phase, respectively. It is interpreted that the diffusion of an alpha stabilizer carbon from TiC into the matrix is one of the plausible reasons far such a microstructural difference. The 0.2% offset yield strengths of the hot pressed TiH₂and TiH₂-45 vol.%TiC samples were 1008 and 1446 MPa, respectively, in a static compressive mode (strain rate of 1×$10^{-3}$/s). Dynamic compressive strengths of the samples were 1600 and 2060 MPa, respectively, at a strain rate of 4×10³/s.

• 한국재료학회지
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• 제9권3호
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• pp.307-314
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• 1999

반응생성에 의한 Ti/TiB 복합재료를 제조하기 위한 반응분말$(TiB_2, B_4C)$, 소결온도, 소결시간을 결정하기 위하여 제조조건에 따른 반응생성상, 미세조직, 상대밀도 등을 조사하였다. 제조된 복합재료의 기계적 성질은 상온 압축항복강도로 평가하였다. 복합재료를 제조하기 위하여 혼합하는 $TiB_2$반응분말의 경우 $1300^{\circ}C, B_4C$ 반응분말의 경우 $1400^{\circ}C$의 소결온도가 최적조건임을 확인하였다. 본 공정에 의해서 제조된 복합재료의 압축항복강도는 비교재인 Ti-6Al-4V 보다 모두 우수하였다. 또한 $TiB_2$반응분말에 의해서 제조된 복합재료가 $B_4C$ 반응분말에 의해서 제조된 복합재료보다 우수한 압축항복강도를 나타내었다. 이는, 압축시험한 복합재료에서의 균열전파양상을 조사한 결과, 강화상과 기지간의 접합특성을 $B_4C$ 반응분말에 의한 복합재료의 접합특성보다 우수하였기 때문이었다.

• 대한기계학회논문집
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• 제18권7호
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• pp.1713-1721
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• 1994

Intermetallic-matrix composites(IMCs) have the potential of combing matrix properties of oxidation resistance and high temperature stability with reinforcement properties of high specific strength and modulus. One of the major limiting factors for successful applications of these composite at high temperatures is the formation of interfacial reactions between matrix and ceramic reinforcement during composite process and during service. The purpose of the present investigation is to develop a better understanding of the nature of creep fracture mechanisms in a $Ni_{3}Al$ composite reinforced with both $TiB_{2}$ and SiC particulates. Emphasis is placed in the roles of the products of the reactions in determining the creep lifetime of the composite. In the present study, creep rupture specimens were tested under constant ranging from 180 to 350 MPa in vacuum at $760^{\cric}C$. The experimental data reveal that the stress exponent for power law creep for the composite is 3.5, a value close to that for unreinforced $Ni_{3}Al$. The microstructural observations reveal that most of the cavities lie on the grain boundaries of the $Ni_{3}Al$ matrix as opposed to the large $TiB_{2}/Ni_{3}Al$ interfaces, suggesting that cavities nucleate at fine carbides that lie in the $Ni_{3}Al$ grain boundaries as a result of the decomposition of the $SiC_{p}$. This observation accounts for the longer rupture times for the monolicthic $Ni_{3}Al$ as compared to those for the $Ni_{3}Al/SiC_{p}/TiB_{2} IMC$. Finally, it is suggested that creep deformation in matrix appears to dominate the rupture process for monolithic $Ni_{3}Al$, whereas growth and coalescence of cavities appears to dominate the rupture process for the composite.

• Composites Research
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• 제32권3호
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• pp.158-162
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• 2019

본 연구에서는 용융가압함침 공정을 이용하여 고체적률의 TiC 입자가 균일 분산된 Inconel 718 금속복합재료를 제조하고, 미세조직 및 기계적 특성을 분석하였다. 약 55 vol%의 TiC가 균일하게 분산된 TiC-Inconel 718 복합재료를 제조함으로써 Inconel 718 대비 우수한 경도 및 압축강도 특성을 나타내었으며, 이는 기지에 고용된 합금원소인 Mo 및 Nb이 TiC 강화재 내부로 확산 고용되어 우수한 계면 특성을 가지는 core-rim 구조의 TiC 형성에 의한 것으로 판단된다.

• Composites Research
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• 제35권4호
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• pp.248-254
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• 2022

본 연구에서는 가스압 함침공정을 이용하여 고체적률 TiB₂-steel 복합재료를 제조하였으며, 미세조직 분석과 압축강도 및 경도를 측정하였다. 복합재료의 미세조직과 기계적 물성과의 연관성을 고찰하고자, 압축시험 후 시편의 파면을 분석하고 압축시험 중 시편의 파괴 거동을 예측하였다. 파면 분석 결과, 기지금속과 강화상 입자간의 계면파괴 흔적이 관찰되었으며, 이에 기지금속과 강화상의 계면을 TEM을 사용하여 분석하였다. 제조된 복합재료의 미세조직 분석 결과, TiB₂ 강화상 및 steel 기지상 이외에 TiC 상과 조대한 (Fe,M)₂B (M=Cr,Mn)상이 생성된 것을 확인할 수 있었으며, 열역학 계산을 통하여 공정조건에서 TiC와 (Fe,M)₂B가 안정상으로 생성될 수 있음을 확인하였다. 제조된 TiB₂-steel 복합재료는 기지 금속 대비 경도가 크게 상승하였으며, 상온 압축강도 및 탄성계수는 각각 3.07배, 1.95배 향상되었다. 복합재료 내부 전반에 생성된 조대한 (Fe,M)₂B (M=Cr,Mn)상이 기계적 물성 저하를 일으키는 것으로 보이며, (Fe,M)₂B (M=Cr,Mn)상의 생성을 제어함으로써 TiB₂-steel 복합재료의 기계적 물성을 추가적으로 향상시킬 수 있을 것이라 생각한다.