Characterization of mechanical properties of Cu-SiC composites using ultrasonics

In this study, the effect of SiC reinforcement on the mechanical, physical properties and microstructure of copper matrix composite contact material was investigated with ultrasonic measurements. The composite materials containing 3-12 vol% SiC reinforced Cu matrix were produced by using the powder metallurgy method. Ultrasonic testing (UT) is one of the most widely used non-destructive testing techniques for the characterization and the evaluation of materials. Also, for the ultrasonic measurements one of the non-destructive methods; pulse-echo technique is used. Changes in ultrasonic velocity, attenuation, Young's modulus and hardness are observed in heat-treated material at pure copper and different SiC reinforcement on copper matrix composite ratio. As a result, the ultrasonic characterizations (longitudinal and shear velocity, attenuation and Young's modulus) and hardness values in all composites increased by the increment in the SiC reinforcement. It is observed that Cu-SiC composites with SiC reinforcements revealed better mechanical properties than pure copper materials.Bu çalışmada, bakır matriks kompozit temas malzemesinin mekanik, fiziksel özellikleri ve mikro yapısı üzerindeki SiC takviyesinin etkisi ultrasonik ölçümlerle incelenmiştir. % 3-12 oranında SiC takviyeli Cu matrisi içeren kompozit malzemeler toz metalurjisi yöntemi kullanılarak üretilmiştir. Ultrasonik test (UT) malzemelerin karakterizasyonu ve değerlendirilmesi için en yaygın kullanılan tahribatsız muayene tekniklerinden biridir. Ayrıca, ultrasonik ölçümler için tahribatsız yöntemlerden biri olan Pulse-eko tekniği kullanılmıştır. Isıl işlem görmüş malzemede saf bakır ve bakır matriks kompozit oranı üzerinde farklı SiC takviyesinde ultrasonik hızında, zayıflamada, Young's modülünde ve sertlikte değişiklikler gözlenmiştir. Sonuç olarak tüm kompozitlerde, ultrasonik karakterizasyonlar (boyuna ve enine hız, zayıflama ve Youngmodülü) ve sertlik değerleri SiC takviyesindeki artış ile artmıştır. SiC takviyeli Cu-SiC kompozitlerinin saf bakır malzemelerden daha iyi mekanik özellikler gösterdiği görülmüştür

WC/Co-Ti Kompozitlerinin ısıl ve elastik özelliklerinin ultrasonik dalga hızı ile ilişkisi

In this study,it is aimed to produce various composites and reveal their physical properties. Tungsten carbide (WC) powder and the two of cobalt (Co) and titanium (Ti) powders as binder phase have been used for the preparation of WC-Co-Ti ceramic-metal composite with powder metallurgy. Two different ultrasonic non-destructive techniques were employed to measure the mechanical wave velocity in WCCo-Ti composites. The study was performed on various specimens with different WCx content at the range from 60 to 80% and Co/Ti content in 3:1, 1:1 and 1:3 groups. The WCx content in examined materials was determined using the standard destructive analysis. The Young modulus (E) of the produced composites and the ultrasonic velocity measured through ultrasonic pulse-echo method and immersion method. Thermal conductivity of samples has been measured via hot disk method. The relation between the Young modulus' values with ultrasonic wave velocity, which is obtained through two different methods and thermal conductivity has been physically examined and the results have been compared with the literature

PREPARATION AND CHARACTERIZATION OF PHYSICO-MECHANICAL AND STRUCTURAL PROPERTIES OF PHTHALIMIDE DERIVATIVE POLYMERIC NANOCOMPOSITES

In this study, phthalimide derived polymer-TiO2 nanocomposites were prepared by direct mixing method and their mechanical properties were compared. The high content filler polymer nanocomposites with sufficient interface bonding with the polymer matrix have been prepared to maximize the properties of the filler. In the direct mixing method, the polymer obtained by free radical polymerization of the monomer was mixed with TiO2 in high weight percentages. The pulse-echo method was used to characterize the elastic constants of the polymer and polymer-TiO2 nanocomposites through detection of the ultrasonic waves. Transverse and longitudinal ultrasonic velocities have been used to calculate Young's modulus of these samples. The ultrasonic velocity and Young's modulus values of polymer-TiO2 nanocomposites showed a linear relationship with the weight percentage of the polymer, which is due to the strong and effective interaction between the particles resulting from by reinforcing TiO2 to the polymer structure. The clustering that emerged with the increase in the amount of reinforcement in the SEM images became more pronounced and it was observed that pure polymer and TiO2 were homogeneously distributed. The porosity and hardness measurements of the polymer and polymer-TiO2 nanocomposites were examined. The hardness and porosity of the polymer structure approximately increased as the percentage values of TiO2 increased. Moreover, TGA results of polymer nanocomposites obtained by direct mixing showed that the thermal stability increased linearly as the weight ratio increase of TiO2 in comparison with the pure polymer.Mus Alparslan University Scientific Research Projects (MSU-BAP) Unit [MSU15-FEF-G03]This work was supported by Mus Alparslan University Scientific Research Projects (MSU-BAP) Unit with the project number MSU15-FEF-G03

Correlation between poisson's ratio, hardness and elastic moduli of Ti-Cr-Co composite materials

Çalışma, Ti-Cr-Cokompozit malzemelerin ultrasonik özelliklerini araştırmayı amaçlamaktadır. Deneysel olarak üretilen ve literatürden toplanan verilere dayanarak, Ti-Cr-Cokompozit numuneleri için Young modülü, Kayma Modülü ve Poisson oranı arasında bir ilişki kurulmuştur. Poisson’ın oranının, borlanmış ve borlanmamış Ti-Cr-Cokompozitlerde artan ultrasonik hız ile yaklaşık olarak azaldığı bulunmuştur. Ayrıca, Youngmodülünde ve kayma modülünde, sertleşmemiş ve sertleştirilmiş Ti-Cr-Cokompozit örneklerinin sertliğindeki değişimler incelenmiştir.Study aims to investigate the ultrasonic properties of Ti-Cr-Co composite materials. A correlation between Young's modulus, Shear Modulus and Poisson’s ratio has beenestablished for Ti-Cr-Co composite samples, based on the data produced experimentallyandcollected from the literature. Poisson’s ratio has been found to approximelydecrease with increasing ultrasonic velocity in borided and non-borided Ti-Cr-Co composites. Also, the variations in Young's modulus and shear modulus with hardness of non-borided and borided Ti-Cr-Co composites samples are investigated, respectively