• Title/Summary/Keyword: Al borate whisker

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Microstructure and Mechanical Properties of Ni3Al Matrix Composites with Fine Aluminum Oxide by PM Method

  • Han, Chang-Suk;Choi, Dong-Nyeok
    • Korean Journal of Materials Research
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    • v.28 no.9
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    • pp.495-498
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    • 2018
  • Intermetallic compound matrix composites have been expected to be established as high temperature structural components. $Ni_3Al$ is a representative intermetallic alloy, which has excellent ductility even at room temperature by adding certain alloying elements. $Ni_3Al$ matrix composites with aluminum oxide particles, which are formed by the in-situ reaction between the alloy and aluminum borate whiskers, are fabricated by a powder metallurgical method. The addition of aluminum borate whiskers disperses the synthetic aluminum oxide particles during sintering and dramatically increases the strength of the composite. The uniform dispersion of reaction synthesized aluminum oxide particles and the uniform solution of boron in the matrix seem to play an important role in the improvement in strength. There is a dramatic increase in strength with the addition of the whisker, and the maximum value is obtained at a 10 vol% addition of whisker. The $Ni_3Al$ composite with 10 vol% aluminum oxide particles $0.3{\mu}m$ in size and with 0.1 wt% boron powder fabricated by the conventional powder metallurgical process does not have such high strength because of inhomogeneous distribution of aluminum oxide particles and of boron. The tensile strength of the $Ni_3Al$ with a 10 vol% aluminum borate whisker reaches more than twice the value, 930 MPa, of the parent alloy. No third phase is observed between the aluminum oxide and the matrix.

Material Properties of Squeeze Infiltrated Al Borate Whisker Reinforced Mg-3A1-2Ag-1Zn Matrix Composites (용탕가압침투법에 의한 알루미늄 보레이트 강화 Mg-3Al-2Ag-1Zn 금속복합재료의 물성)

  • Kang Hojune;Bae Gunhee;Park Yongha;Han Sangho;Park Yongho;Cho Kyungmox;Park Ikmin
    • Korean Journal of Materials Research
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    • v.15 no.12
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    • pp.791-795
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    • 2005
  • In this study, aluminum borate whisker reinforced Mg-3Al-2Ag-1Zn matrix composites were fabricated by the squeeze infiltration technique. The purpose is to develop materials for elevated temperature applications. Microstructure observation revealed successful fabrication of the metal matrix composites, namely no cast defects such as porosity and matrix/reinforcement interface delamination etc. High temperature hardness and creep rupture properties were improved significantly with addition of Ag to the Al borate whisker reinforced Mg alloy composite. $Mg_3Ag$ phase formed during aging heat treatment could improve creep properties of the Mg matrix composites.

Microstructure and Mechanical Properties of Squeeze Cast AZ91 Mg/Al Borate Whisker Composites (용탕단조법으로 제조된 AZ91 Mg/Al Borate 휘스커 복합재료의 미세조직 및 기계적 특성)

  • Kim, Kwang-Chun;Cho, Young-Su;Lee, Sung-Hak;Park, Ik-Min
    • Journal of Korea Foundry Society
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    • v.16 no.6
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    • pp.537-549
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    • 1996
  • This study aims at investigating the correlation of microstructure and mechanical properties of the AZ91 Mg/Al borate whisker composites fabricated by squeeze csting technique with a variation of applied pressure. Microstructure observation and in-situ fracture tests were conducted on the composites to identify the microfracture process. Detailed microstructural analyses indicated that the grain refinement could be achieved with applied pressure and the little change in volume fraction on reinforcing whiskers could be carried out. It was also found clearly from in-situ observation of crack initiation and propagation that in the composite processed by the lower applied pressure, microcracks were initiated earily at whisker/matrix interfaces, thereby resulting in the drop in strength. In the composite processed by the higher applied pressure, on the other hand, planar slip lines were well developed in the matrix, and then propagated through whiskers without whisker/matrix decohesion. Thus, the effect of the applied pressure on microstructure and mechanical properties can be explained by grain refinement, increased amounts of reinforcements, and improvement of whisker/matrix interfacial strength as the applied pressure in increased.

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Growth Behavior of Aluminum Borate Whisker under 2.45 GHz Electromagnetic Irradiation (2.45 GHz 전자기파 조사하에서 Aluminum Borate Whisker의 성장 거동)

  • 김성완;이상근;김지경;이창희;안진모;신준식;박성수;박희찬
    • Journal of the Korean Ceramic Society
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    • v.40 no.10
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    • pp.998-1004
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    • 2003
  • With starting materials of two different powder mixtures, $Al_2$(S $O_4$)$_3$+xNa$_2$B$_4$ $O_{7}$$.$10$H_2O$(㏖ ratio; x=0.1, 0.7) and ${\gamma}$-Al$_2$ $O_3$+xNa$_2$B$_4$ $O_{7}$$.$10$H_2O$(㏖ ratio; x=0.1, 0.7), whisker-type $Al_{18}$B$_4$ $O_{33}$ particles were synthesized by using conventional and microwave heat-treatment. The effects of microwave, amount of flux and temperature on the growth of whisker-type $Al_{18}$B$_4$ $O_{33}$ particles were investigated by using X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM). With increase of heat-treatment temperature and amount of flux, the size of whisker-type $Al_{18}$B$_4$ $O_{33}$ particles increased in both conventional and microwave heat-treated samples. However, compared to the conventional heat-treated samples, whisker-type $Al_{18}$B$_4$ $O_{33}$ particles were well grown for the microwave heat-treated samples.ted samples.

Effect of Aging on the Interfacial Characteristics of ${Al_{18}}{B_4}{O_{33}}$/AS52 Mg Matrix Composite by Squeeze infiltration (용탕가압침투법으로 제조한 ${Al_{18}}{B_4}{O_{33}}$/AS52 Mg기 복합재료의 계면 특성에 미치는 시효의 영향)

  • Park, Yong-Ha;Park, Yong-Ho;Cho, Kyung-Mox;Park, Ik-Min
    • Journal of Korea Foundry Society
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    • v.28 no.6
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    • pp.268-272
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    • 2008
  • Interfacial characteristics of aluminum borate whisker reinforced AS52 matrix composite was investigated. Peak hardness of AS52 composite was obtained aging at $170^{\circ}C$ for 15h and the aging process was accelerated by the presence of the aluminium borate whisker. The MgO layer, which was the interfacial reaction product between the reinforcement and the Mg matrix, was produced with 20 nm thickness in as-cast condition. As the aging time increased, the thickness of the interfacial reaction layer increased to 50 nm in peak aged condition. The nano-indentation test results indicated that the strength of interface was improved by the aging but over-aging degraded the reinforcement and decreased the interfacial strength which resulted in the decrease of overall composite strength.

Fatigue Strength Characteristic of Metal Matrix Composite Material in $9Al_2\;.\;2B_2O_4$/ AC4CH ($9Al_2\;.\;2B_2O_4$/ AC4CH 금속기 복합재료의 피로강도 특성)

  • Park, Won-Jo;Lee, Kwang-Young;Huh, Sun-Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.10
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    • pp.1583-1589
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    • 2001
  • Metal matrix composites with whisker reinforcements have significant potentials for demanding mechanical applications including defense, aerospace, and automotive industries. Especially metal matrix composites, which are reinforced with aluminum borate whisker, have been used leer the part of piston head in automobile because of good specific strength and wear resistance. In this study, AC4CH-based metal matrix composites with $Al_{18}$B$_{4}$ $O_{33}$ reinforcement have been produced using squeeze casting method, after T6 heat treatment, we evaluated fatigue life property of matrix and MMC composite and investigated fracture mechanism.m.

Manufacture and Mechanical Properties of $ABO_w/AC4CH$ Composite Material ($ABO_w/AC4CH$복합재료의 제조 및 기계적 특성)

  • 허선철;박원조;허정원
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.5
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    • pp.188-194
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    • 2001
  • Metal matrix composites with whisker reinforcements have significant potential for demanding mechanical applications including defense, aerospace, and automotive industries. Especially, metal matrix composites, which are reinforced with aluminum borate whisker, have been used for the part of piston head in automobile because of good specific strength and wear resistance. Aluminum alloy-based metal matrix composites with whisker reinforcements have been produced using squeeze casting method, which is kind of an infiltration method. In this study, AC4CH-based metal matrix composites with $Al_{18}B$_4$O_{33}$ reinforcement have been produced using squeeze casting method, after T6 heat treatment, we evaluated mechanical properties of matrix and MMC composite were evaluated.

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Creep Properties of Squeeze Infiltrated AS52 Mg/Al18B4O33w Composite (용탕가압침투 AS52 Mg/Al18B4O33w 복합재료의 크리프 특성)

  • Choi, Kye-Won;Park, Yong-Ha;Park, Bong-Gyu;Park, Yong-Ho;Park, Ik-Min;Cho, Kyung-Mox
    • Korean Journal of Metals and Materials
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    • v.46 no.7
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    • pp.412-419
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    • 2008
  • Creep behavior of the squeeze infiltrated AS52 Mg matrix composites reinforced with 15 vol% of aluminum borate whiskers($Al_{18}B_4O_{33}w$) fabricated squeeze infiltration method was investigated. Microstructure of the composites was observed as uniformly distributed reinforcement in the matrix without any particular defects of casting pores etc.. Creep test was carried out at the temperature of 150 and $200^{\circ}C$ under the applied stress range of 60~120 MPa. The creep resistance of the composite was significantly improved comparing with the unreinforced AS52 Mg alloy. The creep behavior of composites might be interpreted with the substructure invariant model successfully for the composite. Threshold stress of the composite exist for the creep deformation of the composite. The analysis of the creep behavior of the composite with threshold stress indicated that creep deformation was controlled by the lattice diffusion process of AS52 Mg matrix at given effective stresses and temperatures. Activation energy was also calculated to check lattice diffusion controlled creep behavior of the composite.

Analysis of Effective Elastic Modulus and Interfacial Bond Strength of Aluminum Borate Whisker Reinforced Mg Matrix Composite by Using Three Dimensional Unit Cell Model (3차원 Unit Cell 모델을 이용한 알루미늄 보레이트 휘스커 강화 Mg 복합재료의 유효 탄성계수 및 계면강도의 분석)

  • Son, Jae Hyoung;Lee, Wook Jin;Park, Yong Ha;Park, Yong Ho;Park, Ik Min
    • Korean Journal of Metals and Materials
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    • v.48 no.5
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    • pp.469-475
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    • 2010
  • In this study, the interfacial bond strength of a squeeze infiltrated $Al_{18}B_{4}O_{33}$/AS52 Mg composite was investigated by using a finite element method. Three types of Mg composites with volume fractions of 15, 25 and 35% were fabricated. Three-dimensional models of the composite were developed by using a unit cell model in order to determine the effective elastic modulus of the metal matrix composite and the interfacial bond strength between the whisker and magnesium matrix. After modeling, numerical results were compared with the experimental tensile test results of $Al_{18}B_{4}O_{33}$/AS52 Mg composites. The results showed that the effective modulus of the composite strongly depended on the interfacial strength between the matrix and reinforcement. Based on the numerical and experimental findings, it was found that the strong interfacial bond was achieved by the interfacial reaction product of 30 nm thick MgO, which led to an improvement in the mechanical properties of the $Al_{18}B_{4}O_{33}$/AS52 Mg composites.

A Study on Fracture Toughness Properties of $Al_{18}B_4O_{33}/AC4CH$ by Binder Additives (바인더 첨가에 따른 $Al_{18}B_4O_{33}/AC4CH$의 파괴인성에 관한 연구)

  • Shin, Dong-In;Jung, Jae-Wook;Park, Won-Jo;Huh, Sun-Chul;Kim, Hyung-Jin
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.61-66
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    • 2003
  • In this paper, the effect of binder additive on the fracture toughness was metal matrix composite produced by squeeze casting method. In this study using the matrix is AC4CH and reinforcement used Aluminum borate whisker. Each MMC was produced by add inanimate binder ($SiO_2,\;Al2O_3,\;TiO_2$) to whiskers for increase the binding together of whiskers. Fracture toughness test were carry out in accordance with the ASTM E-399 standard test method, W=25mm, b=12.5mm CT(half size) specimen. However Base metal AC4CH was not meet the qualification of $P_m/P_Q<1.1$, so that test were performed $J_{IC}$ test. $K_{J_{IC}}$ value was measuring by $J_{IC}$ value change into $K_{IC}$. $J_{IC}$ test was carry out in accordance with the ASTM 1820.

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