Microstructure characteristics in Al-C system after mechanical alloying and high temperature treatment

2004-03-01
In this work elemental powders of Al and 2 wt-% graphite were mechanically alloyed in a high energy horizontal attritor under purified argon atmosphere for 0.5-2 h. Powder mixes were then cold pressed at 1200 MPa and sintered at 550degreesC for between 2-32 It under the same protective atmosphere. Structural evolution was characterised by X-ray diffraction, scanning electron microscopy and transmission electron microscopy techniques. Results revealed that mechanical alloying was very effective in pulverising the powder mix, where after 2 h, the mix was fine enough to oxidise rigorously when exposed to open air. In general however, mechanical alloying was found to be inefficient to synthesise At with C. But after sintering, Al4C3 phase nanosized particles were formed in the microstructure. When the duration of sintering was prolonged, the particle population multiplied in number. Hence because of improvement in dispersion strengthening, the room temperature hardness of the material increased gradually.
POWDER METALLURGY

Suggestions

Nanohardness measurements of heavy ion irradiated coarse- and nanocrystalline-grained tungsten at room and high temperature
El-Atwani, O.; Weaver, J. S.; Esquivel, E.; Efe, Mert; Chancey, M. R.; Wang, Y. Q.; Maloy, S. A.; Mara, N. (Elsevier BV, 2018-10-01)
Heavy ion irradiation was performed on coarse and nanocrystalline-grained tungsten (CGW and NGW, respectively) at room temperature (RT) and 1050 K from 0.25 to 4 dpa to simulate radiation damage for fusion energy applications. TEM and nanohardness measurements of irradiated samples were made to quantify the radiation tolerance of these two candidate materials. In this case, TEM is used to quantify the defect morphology at low dpa values and determine the barrier strength coefficients of the different defect...
Microstructural changes and void swelling of a 12Cr ODS ferritic-martensitic alloy after high-dpa self-ion irradiation
Chen, Tianyi; Aydoğan Güngör, Eda; Gigax, Jonathan G.; Chen, Di; Wang, Jing; Wang, Xuemei; Ukai, S.; Garner, F. A.; Shao, Lin (2015-12-01)
A dual-phase 12Cr oxide-dispersion-strengthened (ODS) alloy, with improved corrosion and oxidation resistance exhibits promising void swelling resistance and microstructural stability under Fe2+ ion irradiation to 800 dpa at 475 degrees C. Dispersoids were originally present in both ferrite and tempered martensite grains, with the latter having a wider range of dispersoid sizes. In both phases dispersoids > 10 nm in diameter are incoherent with the matrix, while smaller dispersoids are coherent. During irra...
Microwave sintering and characterization of soft magnetic powder metallurgical Ni-Fe alloys
Erdem, Derya; Dericioğlu, Arcan Fehmi; Department of Metallurgical and Materials Engineering (2011)
In this study, prealloyed austenitic stainless steel and premixed soft magnetic Ni-Fe permalloy compacts were consolidated through microwave and conventional sintering routes at combinations of various sintering temperatures and compaction pressures. Sintered alloys were characterized in terms of their densification, microstructural evolution as well as mechanical and magnetic properties. The effect of sintering method in terms of the applied sintering parameters on the final properties of the compacts were...
Microstructural characteristics of gas tungsten arc synthesised Fe-Cr-Si-Ccoating
Yılmaz, Osman; Özenbaş, Ahmet Macit (2002-10-01)
The gas tungsten arc (GTA) method was used to synthesise Fe - Cr - Si - C alloy coatings, and processing effects on the coating were investigated experimentally. Coatings were developed on an AISI type 1040 steel substrate. Four different regions were obtained in the surface coating; and in these regions either a hypoeutectic or a hypereutectic microstructure was found. The hypoeutectic microstructure consisted of primary dendrites of austenite (gamma) phase and eutectic M7C3 (M = Cr,Fe) carbides. On the ot...
Performance anallysis of an intermediate temperature solid oxide fuel cell
Timurkutluk, Bora; Tarı, İlker; Department of Mechanical Engineering (2007)
An intermediate temperature solid oxide fuel cell (SOFC) is developed and its performance is investigated experimentally and theoretically. In the experimental program, a gadolinium doped ceria based membrane electrode group is developed with the tape casting and screen printing methodology and characterized. An experimental setup is devised for the performance measurement of SOFCs and the performance of produced cells is investigated over a range of parameters including the electrolyte thickness, the sinte...
Citation Formats
B. BOSTAN, A. Özdemir, and A. Kalkanlı, “Microstructure characteristics in Al-C system after mechanical alloying and high temperature treatment,” POWDER METALLURGY, pp. 37–42, 2004, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35573.