Microstructural Characterisation of As–Cast Binary Near Gamma Titanium Aluminides

Abstract

Sebatian antara logam berasaskan sebatian Ti–Al mempamerkan sifat yang menyakinkan untuk aplikasi suhu tinggi. Walau bagaimanapun, hanya aloi dua fasa hampir gamma mampu sedikit sebanyak memenuhi aplikasi suhu tinggi yang penting. Oleh itu, pada dekad yang lepas, banyak kajian telah ditumpukan kepada mengoptimumkan aplikasi aloi baru ini. Oleh kerana sifat suhu tinggi terutama berkaitan dengan rayapan yang sangat bergantung kepada mikrostruktur, kefahaman menyeluruh mengenai mikrostruktur ini diperlukan. Dalam kertas kerja ini, pengetahuan semasa mengenai mikrostruktur aloi tuangan binari hampir gamma titanium aluminaid akan dibincangkan. Kata kunci: Hampir gamma titanium aluminaid, mikrostruktur, saiz bijian, pecahan isipadu, morphologi sempadan bijian Intermetallics based on Ti–Al compounds exhibits promising properties for high temperature applications. However, only two phase near gamma alloys are able to some extent fulfill the crucial high temperature applications. Therefore during the past decade, a number of research efforts were directed to optimise the application of this recently emerging class of alloy. Since the high temperature property which mainly concerns creep is strongly microstructure dependent, a comprehensive understanding on the microstructure is needed. In this paper, the current knowledge on the microstructures of as cast binary near gamma titanium aluminides will be addressed. Key words: Near gamma titanium aluminides, microstructure, lamellae, nearly lamellae, duplex