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دراسة تاثير سرعة الدوران ودرجة الصب على توزيع السليكون في سبيكة Al - 23% Si بسباكة الطرد المركزي == Study The Effect of Rotation Speed And Pouring Temperature On The Distribution of Si In The (Al - 23% Si) Alloy Produced By Centrifugal Casting
Author name:
عبد الجبار سعد جمعة
Supervisor name:
نوال عزت عبد اللطيف | رابحة صالح ياسين
General topic:
Production engineering metallurgy and materials
Specific topic:
Metals Engineering
Degree:
Master
University:
University of Technology
Language:
Arabic
University location:
Baghdad
First pages:
50T182 - p.pdf
Abstract:
يهدف البحث الى تحضير مادة متدرجة وظيفيا" ( FGM ) باستعمال طريقة السباكة بالطرد المركزي ودراسة تاثير متغيرات العملية على البنية المجهرية لسبيكة المنيوم - سيليكون فوق اليوتكتك (Al - 23%Si ). تمت دراسة تاثير كل من سرعة دوران قالب السباكة ودرجة حرارة الصب ( ا | The aim of this study was to prepare a functionally graded material by using centrifugal casting method and study effect of parameters process on the microstructure of a hypereutectic ( Al - 23%Si) alloy. Effect the rotation speed of mold casting and overheating temperature on the microstructure and hardness of ahypereutectic ( Al - 23%Si) alloy were investigated. Therefore, the melt was overheated to( 800,900) C? and poured in the centrifugal casting mold after preheating by used gaseous torch to (100) C?. Then we obtained on cylinders at different rotation speed (765,840,1043,1712,1878) r.p.m. Optical microscopy and scanning electron microscopy used to study the microstructure to produce samples. The results showed that the overheating temperature and mold rotation speed affect on the grain size and volume fraction of ( ? - Si) phase, increasing of the overheating temperature due to increasing average volume fraction and decreased the grain size of primary silicon, but increasing mold rotation speed due to increasing the average volume fraction in the inner layer from cylinder thickness and decreased in the intermediate and outer layer , also decreased the grain size of primary silicon. The maximize volume fraction was in the inner layer from a cylinder thickness obtained at rotation speed (1878) r.p.m. and poring temperature (900)C? , where the values of volume fraction of ( ? - Si) phase are (35%) and obtained on completely functionally graded material. The results of micro structural observations showed that centrifugal casting process contributed to change the eutectic phase morphology from coarse needle - like structure to fibrous structure at increasing mold rotation speed but increased pouring temperature due to invert, and the results showed found thickness of (Si) particles in the metallic matrix decreased with increased rotation speed. The results of hardness tests to a cylinders samples showed maximum hardness values in the inner layer from cylinder thickness and increased with increasing mold rotation speed but it is decrease with increasing rotation speed. values hardness in all layers decrease with increasing pouring temperature. The results of wear tests showed maximum wear resistant was in the inner layer from cylinder thickness at rotation speed (1878) r.p.m. and poring temperature (800)C? and then coming outer layer but minimum wear resistant was in the intermediate layer.
