EXISTENCE FORM OF RE ELEMENT Nd AND ITS EFFECT ON THE FORMATION OF Ti_3X PHASE
稀土Nd在Ti合金中的存在形态及其对Ti_3X相析出的影响

The existance form of RE element Nd and its effect on the precipitation ofTi_3X phase in Ti-Al-Nd alloy were investigated by TEM and X-ray diffraction techniques.The results show that the existance form of RE element Nd in Ti alloy is mainlyNd_2O_3 particles,which is the product of internal oxidation during melting and casting.The re-sults also show that the size of Nd_2O_3 particles is about 100-200nm and its structure is bcc.Thestrengthening role of Nd in titanium alloy is the combined interaction of Nd_2O_3 particles withdislocations.The depression effect of Nd on the Ti_3X phase formation is attributed to its low-ering the oxgyen concentration by internal oxidation and then lowing the average electron con-centration.