EFFECTS OF YTTRIUM ADDITION ON HIGH TEMPERATURE OXIDATION RESISTANCE OF ALUMINA FORMING AUSTENITIC STAINLESS STEEL: CRITICAL REVIEW

• Main Author: Indra, Vincentius
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/48179
• Institution: Institut Teknologi Bandung

Alumina forming austenitic stainless steel (AFA SS) which was developed by Oak Ridge National Laboratory is a promising candidate for high temperature applications. This type of alloys possesses satisfactory high temperature oxidation resistance, creep performance similar to advanced austenitic stainless steels, and may be used as a low-cost alternative to Ni-base alloys. AFA SS applications include turbine recuperators, steam boilers, SOFC, and etcetera. In the present study, the effects of yttrium addition on high temperature oxidation resistance of alumina forming austenitic stainless steel has been investigated by reviewing previously published research results, ranging from scientific publications, journals, research report, thesis, etc. First of all, collection of published research papers, containing key words: yttrium, oxidation, high temperature, austenite, stainless steel, or alloy is conducted. Second, elimination of irrelevant research results is undertaken. Third, an analysis of the collected research papers is done in regard to answering research objectives. Fourth, comparison of research results, finding unanswered questions from other sources, and consultation to textbooks are done, especially in building suggestions for future research. Fifth, conclusion is derived from the conducted critical review. From the conducted critical review, the following conclusions are devised. Addition of yttrium is found to: 1) decrease the oxidation kinetics of AFA stainless steel, 2) decrease grain growth rate due to increased activation energy, and 3) change the diffusion mechanism from mixed diffusion into inward diffusion which is beneficial to adhesion of alumina scale. In order to cope with the limitations of this literature review, the following suggestions are made: three experiments with different objectives should be made: 1) to investigate the influence of grain boundary diffusion towards oxidation behaviour and kinetics, 2) to investigate the role of oxide pegs on increasing cyclic oxidation resistance, and 3) to investigate the beneficial nature of yttrium with same or similar grain size to eliminate any influence from grain boundary.