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H. Rudianto, G.J. Jang, S.S. Yang, Y.J. Kim and I. Dlouhy

Abstract

Premix Al-5.5Zn-2.5Mg-0.5Cu alloy powder was analyzed as matrix in this research. Gas atomized powder Al-9Si with 20% volume fraction of SiC particles was used as reinforcement and added into the alloy with varied concentration. Mix powders were compacted by dual action press with compaction pressure of 700 MPa. High volume fraction of SiC particles gave lower green density due to resistance of SiC particles to plastic deformation during compaction process and resulted voids between particles and this might reduce sinterability of this mix powder. Sintering was carried out under ultra high purity nitrogen gas from 565°-580°C for 1 hour. High content of premix Al-5.5Zn-2.5Mg-0.5Cu alloy powder gave better sintering density and reached up to 98% relative. Void between particles, oxide layer on aluminum powder and lower wettability between matrix and reinforcement particles lead to uncompleted liquid phase sintering, and resulted on lower sintering density and mechanical properties on powder with high content of SiC particles. Mix powder with wt90% of Alumix 431D and wt10% of Al-9Si-vf20SiC powder gave higher tensile strength compare to another mix powder for 270 MPa. From chemical compositions, sintering precipitates might form after sintering such as MgZn2, CuAl2 and Mg2Si. X-ray diffraction, DSC-TGA, and SEM were used to characterize these materials.

Open access

H. Rudianto, C. Edtmaier, I. Dlouhy and F. Soukal

Abstract

CNT has been researched significantly due to its properties especially mechanical and conductivity properties. Due to strong affinity between particles, dispersion has been remained a problem for its applications. Ultrasonication technique was used to disperse CNT on aluminum powder. Ultrasonication has successfully dispersed CNT on aluminum powder in ethanol. Low energy ball milling for 1h under argon gas with 5:1 ball to powder ratio was used to optimize dispersion of CNT on aluminum. CNT concentration in this research is ranged from 0.1 up to 3wt%. Premix Al-5.5Zn-2.5Mg-0.5Cu powder was used as matrix for this research. Sintering at 580°C for 1h under argon gas was carried to produce high density materials. Pores are still remained on material and it is possibility that pores were caused by agglomeration of CNT. Dispersion high content of CNT is still remained obstacle on this research. Aluminum carbide, Al4C3 is recognized as a ‘bridge between aluminum and CNT for stress transfer was investigated in this research. Raman Spectroscopy, XRD and SEM-EDS were carried out to characterize materials.