EFFECT OF ALLOYING ELEMENT ON MECHANICAL PROPERTIES OF Fe_3 AL AND FeAI ALLOYS

The effect of alloying element such as Mo,Si or B and its stoichoimetric composition on thetensile properties at room and elevated temperatures,and also on the microstructure of Fe_3Aland FeAl alloys has been investigated.Two Fe aluminides were found to be obviouslystrengthened by all of three elements,but seriously embrittled by Mo and Si.An improvemenover the plasicity of FeAl may be made by adding B,and the fracture surface is variedfromintergranular to transgranular cleavage type.The room temperature plasticity of the Fe-richFe_3Al or Al-rich FeAl is much better than that of the stoichoimetric aluminides.An anoma-lous temperature dependence on the yield strength of Fe_3Al in range of 400 to 500℃ or ofFeAl in range of 400 to 500℃ was found.Discussion has been carried out by the aspect ofmicrostructure.