| In aerospace industry, in order to increase thrust-weight ratio of the aero-engine and rocket efficiently, the reqirement of the materials is high specific strength. Titanium alloy is widely used because it is one of the highest specific strength materials. The Ti alloy used in aero-engine requires not only having excellent mechanical property and process ability at room temperature but also having certain strength and plasticity at 300~650℃. With the increasing of temperature, the property of some titanium alloys like Ti-6242 cannot satisfy the requirement of the engine(especially high temperature performance)TC25 alloys are α+β titanium alloys with good resistance against heat, which belongs to Ti-Al-Zr-Sn-Mo-W martensite. The nominal composition is Ti-6.5Al-2Mo-1Zr-1Sn-1W-0.2Si. It has been scale produced and applied in aero-engine. The prominent character of the alloy is that it owns high-melting-point elements W,Mo. According to this, some research have been done: the production of intermediate alloys including W and Mo,the melting technology of Φ 720 mm ingots melting in VAR、the alloying way of TC25 and the control of the uniformity in ingots’ composition and the metallurgical quality.The result shows that:(1) the chemical composition of Al-Mo-W-Ti is well-distributed; the deviation among main elements is small in the same batch.(2) the uniformity in ingots’ composition and the metallurgical quality can be ensured by the batching of intermediate alloys 、the matching of raw material particle size、the mechanical mixing ways、the weld of electrodes in vacuum welding chamber and the melting technology of ingots melting in VAR.(3) the segregation and inclusions have not been detected in bar、disk、ring produced by TC25 which meet the standards’ requirement. |
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