Studies on Alumina Dispersion–Strengthened Copper Composites Through Ball Miling and Mechanical Alloying Method

Abstract

Kuprum diperkuat–serakan oksida berkemampuan untuk mengekalkan sifat–sifatnya pada suhu tinggi. Di antara pelbagai proses, kaedah penghasilan serbuk logam adalah terbaik disebabkan oleh kecekapannya dalam penyebaran partikel oksida yang halus. Dalam kajian ini, komposit kuprum–alumina dihasilkan menerusi kaedah serbuk logam yang mana serbuk matriks kuprum ditambah kepada alumina yang berfungsi sebagai penguat. Campuran serbuk dengan komposisi alumina yang berbeza telah disediakan (2.5% berat, 5% berat, 7.5% berat dan 10% berat). Campuran tersebut kemudiannya dicampur melalui dua kaedah berbeza samada: (a) proses percampuran selama 45 minit dengan pengisar bebola atau (b) proses pengaloian mekanikal selama 45 minit dalam pengisar planet. Ini diikuti dengan penekanan campuran serbuk pada 200 MPa dan persinteran dalam argon pada 950°C selama 1 jam. Keputusan menunjukkan kaedah pengaloian mekanikal telah menghasilkan komposit Cu–AI203 dengan kekerasan yang lebih tinggi dan kekonduksian elektrik yang lebih rendah berbanding kaedah pengisaran bebola. Kata kunci: Komposit kuprum-alumina, pengaloian mekanik, pengisaran bebola, kekonduksian elektrik Oxide dispersion–strengthened copper has the ability to retain most of its properties at elevated temperatures. Among various processes, powder metallurgy route is ideal because of its efficiency in dispersing fine oxide particles. In this study, copper–alumina composites is produced through powder metallurgy route whereby copper powder, which is the matrix, was mixed with alumina powder, which act as reinforcement. Powder mixtures with different compositions of alumina (2.5wt%, 5wt%, 7.5wt% and 10wt%) were prepared. The mixtures were then mixed either by (a) blending process for 45 minutes in a ball mill or (b) mechanical alloying for 45 minutes in a planetary mill. The mixture was then compacted at 200 MPa and sintered under argon atmosphere at 950°C for 1 hour. Results showed that mechanical alloying has produced Cu–AI2O3 composite with better hardness and lower electrical conductivity compared to those prepared by ball milling method. Key words:Copper-alumina composites, mechanical alloying, ball milling, electrical conductivity