对TiAI合金涡轮的立式离心熔模陶瓷型壳精密铸造进行了研究，合金熔配设备为水冷铜坩埚真空感应熔化炉。首先研究了TiAI合金铸造时的尺寸收缩问题，结果表明1600℃浇注时，合金的收缩率为1.32%随着浇注温度的提高凝固收缩率显著提高。从合金熔体立式离心力场下充型模式方面考虑，涡轮浇注工艺应采用类似于重力充型的底注式较好。 TiAI合金涡轮离心浇注内部组织致密、无气孔，存在的主要问题是欠浇缺陷，迎流面充型较弱。可以从提高离心转速 和浇注温度两方面解决欠浇缺陷，但离心转速提高带来的安全隐患以及提高浇注温度带来的粘砂问题还需进一步研究。

对水冷铜坩埚真空感应熔炼过程中合金元素的挥发动力学进行了深入的分析，并在此基础上建立了ISM熔炼过程中A1元素挥发控制方式的判断模型。对Ti-48Al-2Cr-2Nb（at%）和Ti-24Al-11Nb（at%）合金中A1元素挥发控制方式的判断结果表明：随着熔体温度的升高和外压的增大，Al元素的挥发由低温和高压时的界面挥发控制向高温和低压时的界面挥发和液相中扩散同时起作用的双重控制方式转变，只是对于不同的合金，其转变温度和转变压力不同。外压为O.1333 Pa时，Ti-48Al-2Cr2Nb和Ti-24Al-11Nb合金中A1元素挥发控制方式的转变温度分别为1950K和2000K左右；熔体温度为2073K时，因为不同合金中A1元素饱和蒸汽压不同，这2种合金中Al元素挥发控制方式的转变压力分别为133.3 Pa和66Pa左右。

在航空航天及能源领域有重要应用价值的TiAl基合金，由于其γ+α2 片层结构的特点，采用定向凝固技术控制片层方向可以更好地发挥其潜能。从相与组织选择及晶体择优生长特性角度，讨论了具有包晶反应的高温γ-TiAl 合金的定向凝固与晶向控制，分析了晶向控制中引晶、合金化、调节成分与凝固参量及它们的综合作用所得到的结果与存在的问题，并提出了此领域今后应注意的方面。

The properties of intermetallic compounds are sensitive to alloy composition and Interstitial element content determined bythemelting process. Induction skullmeltingis oneofthe bestmethodsformelting reactive alloys. For induction heating under vacuum, melt temperature control is problematic. A numerical model tar simulating temperature field during induction skull melti'ng has been developed using the direct finite difference method. Factors such as water cooling boundaries, electromagnetic stirring meniscus, and power distribution in the charge were analysed. The charge/crucible interface was taken as a radiation boundary betore melting and as a combined radiation and conduction boundary after melting. The frce snrface was taken as a radiation boundary. I he relationship between the height of electromagnetic stirring meniscus and charge weight and melting power was reduced based Oll the conservation ofmass. Based on the conservation ofenergy, the distribution density ol induction current was ascertained. With the program. the relationship beWveen melting power, charge weight,and melt temperature was established. During induetion skull melting of 7-I' iAl based alloys, the melt temperature was meas Llred carefully. The theoretical and experilnental results were found to be in agreement.

The change of the skull shape and size has been predicated through computer simulation technique and com-pared with the experimental results. The microstructure of the skull and the elemental line distribution in the skull have been analyzed with optical microscope and EPMA etc. The results show that the skull height and thickness become small with increasing melting power; the skull consists of two zones, that is, fine equiaxial crystal zone and coarse columnar crystal zone; there exists some segregation in the bottom of the skull.