سال انتشار: ۱۳۹۱

محل انتشار: اولین همایش بین المللی و ششمین همایش مشترک انجمن مهندسی متالورژی ایران

تعداد صفحات: ۲۵

نویسنده(ها):

M.H Norouzi – School of Metallurgy and Materials Engineering, University of Tehran, P.O. Box 14395-731, Tehran, Iran
M Emamy –

چکیده:

The effect of modification on the microstructure and tensile properties of in situ Al-15% Mg2Si composite have been investigated.The Al-15%Mg2Si composite ingot was made by an in-situ process and different amounts of phosphorous were added to the remelted composite. It was found that the morphology of primary Mg2Si particules changes from dendritic to polygonal shape, and their average size decreases from 43 to 4μm. The morphology of eutectic Mg2Si phase also changes from fibriform to short fibriform and/or dot-like,while the eutectic Si phase does not change obviously after the composite was modified.The results obtained from tensile test indicate ultimate tensile strength (UTS) of the modified composite was 304 MPa with 3.82% elongation, while the as-cast composite has UTS value of 250MPa with 2.38% elongation. According to the results, the optimum tensile property was achieved by adding 0.5 wt.% P to the Al-Mg2Si composite . Scanning electron microscopy was employed to examine the crack nucleation and fracture model. The results indicated that Al–۱۵%Mg2Si composite shows different behaviours of crack initiation and fracture for samples with and without P. Differences observed in the fracture behaviour were attributed to microstructural changes as well as morphological aspects of primary Mg2Si particles