Based on the addition of 0.4%Sn to Mg-Y-Cu alloy

effects of DC magnetic field in range of 0～1.4 Ton solidification structure

crystallization orientation and mechanical properties of Mg-Y-Cu-Sn alloy were investigated.The results show that with the increase of magnetic field intensity

the grain size of the alloy is decreased firstly and then increased

and the turning point is 0.35 T

while change of the second phase volume fraction is increased firstly and then decreased.With the increase of magnetic field intensity

the crystallization orientation of the alloy is changed constantly.When the magnetic intensity is 0.7 T

the diffraction peak ofα-Mg on（100）surface is enhanced

forming an obvious crystal orientation.Meanwhile

the alloy presents the highest tensile strength and the lowest elongation.When the magnetic field intensity is 1.4 T

the crystallization orientation ofα-Mg is formed on（002）and（101）surfaces.And the alloy has the desirable comprehensive mechanical performance

and its tensile strength and elongation are increased by up to 34.5%and 32%

respectively

compared with those of the alloy without magnetic field treatment.