• 한국재료학회지
• /
• 제28권9호
• /
• pp.495-498
• /
• 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.

• 한국주조공학회지
• /
• 제17권2호
• /
• pp.164-169
• /
• 1997

Mechanical properties of aluminum-matrix composites, fabricated by dispersion of fine SiC particulates of which size was less than 1 ${\mu}m$ into 2024 and 7075 aluminum alloys, have been investigated. Homogeneous mixing between the matrix and SiC particulates could be achieved by jar milling for 8 hours with appropriate processing agent. At temperatures below 473K, high-temperature tensile strength of the composites was higher than that of the 2024 and 7075 aluminum alloys which were used as matrix materials. However, tensile strength of the composites was approximated to that of the matrix materials at 573K. Thus, it could be suggested that effects of particle dispersion on tensile strength of aluminum alloys was diminished at temperatures higher than 573K.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.1061-1062
• /
• 2006

This paper presents a new approach for analyzing the microstructure of $SiC_p$-reinforced aluminum matrix composites from digital images. Various samples of aluminum matrix composite were fabricated by hot pressing the powder mixtures with certain volume and size combinations of pure Al and SiC particles. Microstructures of the samples were analyzed by computer-based image processing methods. Since the conventional methods are not suitable for separating phases of such complex microstructures, some new algorithms have been developed for the improved recognition and characterization of the particles in the metal matrix composites.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.1303-1304
• /
• 2006

The type, volume fraction, size, shape and arrangement of embedded particles influence the mechanical properties of the particle reinforced metal matrix composites. This presents the investigation of the SiC particle and porosity distributions in various aluminum matrix composites produced by cold- and hot-pressing. The microstructures were characterized by optical microscopy and stereological parameters. SiC and porosity volume fractions, and the anisotropy distribution function were measured to establish the influence of the consolidation method.

• 한국주조공학회지
• /
• 제21권6호
• /
• pp.359-365
• /
• 2001

The superplastic behavior of whisker reinforced aluminum alloy matrix composites fabricated by squeeze casting as one of high pressure routes was investigated. The preforms of ${\alpha}-Si_3N_4$ and ${\beta}-SiC$ whiskers without any binder as a reinforcement were used. The matrix materials were 2024 and 7075 aluminum alloys. For the purpose of optimum superplastic condition, respectively, the whiskers volume fraction, extrusion temperature, tensile test temperature and initial strain rate were changed. Fracture surface of tested specimens were observed by SEM. By the results, it became possible to produce superplastic composites by applying only a hot extrusion process to composites obtained by the squeeze casting. The superplastic composites developed are ${\alpha}-Si_3N_4w/7075$, ${\alpha}-Si_3N_4w/2024$ and ${\beta}-SiCw/2024$ systems at high strain rate.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2004년도 추계학술발표대회 논문집
• /
• pp.35-38
• /
• 2004

Graphite nanofiber (GNF) and carbon nanotube (CNT) are novel fiber reinforcing materials which have outstanding physical and mechanical properties. Aluminum matrix composites reinforced graphite nanofiber were fabricated by conventional powder metallurgy (PM) method. The composites were prepared through ultrasonication, ball milling, and hot isostatic pressing. A uniform distribution of GNF in aluminum matrix could be obtained. To measure the mechanical properties of GNF-Al composites testings were done in indentation and compression. The compressive strength was enhanced according to reinforcing graphite nanofiber while the hardness was decreased. This study makes the high performance composites for future applications.

• 한국자동차공학회논문집
• /
• 제9권5호
• /
• pp.188-194
• /
• 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.

• Composites Research
• /
• 제36권2호
• /
• pp.101-107
• /
• 2023

본 연구에서는 질화알루미늄을 강화재로 갖는 알루미늄기지 복합재료를 질소 분위기에서의 아크용해 공정을 통해 제조하였다. 알루미늄과 질소 원자의 화학반응을 1분간 유지시켰을 때, 중간층과 라멜라층으로 구분되는 질화알루미늄 강화상이 자발적으로 알루미늄 용탕 내부에 형성되어 기지 전반에 분포되었다. 복합재료는 약 10 vol.%의 AlN을 가지며, 이 강화재는 계면에서 낮은 열저항과 강한 결합을 보였다. 제조된 복합재료는 열전도도가 높고 열팽창계수는 낮은 열적 특성 조합을 보였다. 또한, 본 연구의 복합재료는 이종원소인 실리콘을 기지에 첨가함으로써 열팽창계수를 추가적으로 감소시키는 것이 가능했다. 이는 아크 용해법으로 제조된 알루미늄기지 복합재료가 낮은 열팽창계수를 요구하는 방열소재로 적용될 수 있는 가능성을 시사한다.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.1294-1295
• /
• 2006

Various reactions and the in-situ formation of new phases can occur during the mechanical alloying process. In the present study, Al powders were strengthened by AlN, using the in-situ processing technique during mechanical alloying. Differential thermal analysis and X-ray diffraction studies were carried out in order to examine the formation behavior of AlN. It was found that the precursors of AlN were formed in the Al powders and transformed to AlN at temperatures above $600^{\circ}C$. The hot extrusion process was utilized to consolidate the composite powders. The microstructure of the extrusions was examined by SEM and TEM. In order to investigate the mechanical properties of the extrusions, compression tests and hardness measurements were carried out. It was found that the mechanical properties and the thermal stability of the Al/AlN composites were significantly greater than those of conventional Al matrix composites.

• Advances in materials Research
• /
• 제9권2호
• /
• pp.99-107
• /
• 2020

Reinforced aluminum alloy base composites have become increasingly popular for engineering applications, since they usually possess several desirable properties. Recently, Warm Accumulative Roll Bonding (WARB) process has been used as a new novel process to fabricate particle reinforced metal matrix composites. In the present study, TiO₂ particles are used as reinforcement in aluminum metal matrix composites fabricated through warm accumulative roll bonding process. Firstly, the raw aluminum alloy 1060 strips with TiO₂ as reinforcement particle were roll bonded to four accumulative rolling cycles by preheating for 5 min at 300℃before each cycle. The mechanical and bonding properties of composites have been studied versus different volume contents of TiO₂ particles by tensile test, peeling test and vickers micro-hardness test. Moreover, the fracture surface and peeling surface of samples after the tensile test and peeling test have been studied versus different amount of TiO₂ volume contents by scanning electron microscopy. The results indicated that the strength and the average vickers micro-hardness of composites improved by increasing the volume content of TiO₂ particles and the amount of their elongation and bonding strength decreased significantly.