TA19钛合金中半等轴组织特征与拉伸性能研究

Study on the Semi-equiaxed Structure and Tensile Properties of TA19 Titanium Alloy

摘要:

本文采用TA19合金加热到β相变点以上短时保温25-90s,得到了介于等轴组织与片层组织间的一种具有半等轴特征的过渡组织,研究了随保温时间的变化对半等轴组织演变规律及对力学性能的影响。结果表明半等轴组织主要是在β相变点以上短时保温时,β基体中的合金元素Mo向原等轴α相中扩散不均匀,冷却转变过程中初生等轴α相局部被β转变组织分割所形成。随保温时间的延长,半等轴特征逐渐被片层组织所取代,在保温温度为45s时,抗拉强度1219MPa,断面收缩率29%,伸长率14%,具有较好的强塑性。

Abstract:

By heating up the T_β temperature and then holding 25-90s, the semi- equiaxed structure, which is a transition structure between the equiaxed structure and the lamellar structure,is shaped. The influence of the change of heat holding time on the semi-equiaxed structure evolution law and mechanical properties is studied. Experimental results indicate that the formation of the semi-equiaxed structure is mainly because the element Mo into the β matrix diffused inhomogeneous into primary equiaxed α phase when specimens was kept above the T_β temperature for a short time,And in the cooling process,the β transformain structure grow through the primary equiaxed α phase.With the prolongation of holding time,the semi-equiaxed structure are gradually replaced by lameller structure.When heated to 1015℃,hold 45s,the tensile strength is 1219MPa,the reduction of area is 29%,and the elongation is 14%,which has a better strength and plasticity.