B元素对TA15合金铸态组织的改性与机理研究

Research and Mechanism of Modified with Boron Element on As cast Microstructure of TA15 Alloy

研究了B元素对TA15钛合金铸锭铸态组织形貌的影响,并对这种形貌随B元素含量不同而发生的变化进行分析,得出TA15铸锭中加入B元素后可显著细化铸锭晶粒,且随B元素含量的升高,细化程度提高。B元素对TA15钛合金铸锭铸态组织细化机理:B元素作为间隙元素在β相中的溶解度很低,且在凝固过程中形成TiB化合物。因此B元素可通过成分过冷,提高非均匀形核速率以达到细化晶粒的目的。同时,TiB化合物对晶界产生钉扎,抑制了晶粒的进一步长大,进而细化组织晶粒。

The influence of boron on the cast microstructure of TA15 titanium alloy ingots was studied, and the morphology with different boron content and the change rules were analyzed. The adding boron element TA15 in the ingot can significantly refine ingot grain, and with the increase of boron elementrefinement, the degree of conclusion improves. The refinement mechanism of TA15 titanium alloy ingot to boron is： boron element as themiscibility gap element in the beta phase is very low,and the formation of TiB compounds in the solidification process, therefore boron may be through the composition undercooling,improve the heterogeneous nucleation rate in order to achieve the purpose of grain refinement. At the same time, TiB compounds produce the pinning of grain boundaries, inhibit the growth of grain, and then refine the grain size.