| Titanium alloys possess low density, high specific strength and good corrosion resistant, which can match the demand of modern aviation engine very well, so the compressor disk is the most common parts used titanium alloys. With the increase of the thrust-mass ration of the new high performance aviation engine, the temperature and the rotate speed of the compressor disk must be enhanced. Therefore, the compressor disk should undergo much stronger stresses both in mechanical condition and thermal condition during working. If using the traditional compressor disk with single structure, it could not make full use of the property of the material, some parts are rich in property and some are poor. Through strain controllable forging to achieve the dual property compressor disk with equiaxed structure in the core and basketweave structure in the rim can exert full potential property of material, and satisfy the demand of high thrust-mass ration of engine.Studing the influence of processing parameters on the globularization of lamellar a microstructure in Ti-17 alloy is the key technique of producing the dual-property compressor disk using strain controllable forging. In this thesis, isothermal compression test, metallurgical analysis, isothermal forging, theory of processing map and SEM were used to analyze the hot deformation behavior, the effect of processing parameters on the globularization and the globular mechanism. The main conclusions show that:1. Ti-17 alloy is sensitive to the variety of temperature and strain rate, and the flow curves exhibited a peak stress followed by flow softening. At high strain rate, typically 10s-1, discontinuous yielding followed by flow oscillations was observed in β phase region.2. The deformation degree is the major factor of globularization. At optimal temperature and strain rate, the lamellar structure can fully globularize when ture strain reached 0.8 and the order of strain was much lower than Ti-6A1-4V, which strains of the order of 2-2.5 were required to yield an almost fully globularized microstructure.3. A new hyperbolic sine constitutive equation described by the parameters Zener-Holloman was proposed in Ti-17 and well verified by the experiment.4. The processing map of Ti-17 alloy was firstly established. As a result, the optimum processing condition of globularization of lamellar a for Ti-17 alloy is during 840-870℃, 0.5~3s-1; Ti-17 alloy exhibits flow instability regimes due to adiabatic shear bands formation at higher strain rates(>5s-1) at 870~910℃.5. The processing map of Ti-17 alloy was verified by the isothermal forging.The mechanical property of three different microstructure achieved by different strain (30%, 40%, 80%) was tested. It shows that, obtaining different mechanical property by controlling the strain which makes different microstructure is doable.6. The mechanism of globularization for Ti-17 alloy during the hot deformation is similar to model which was proposed by Margolin and Cohen: firstly, the subboundaries were formed within the lamellar a by means of dynamic recrystallization; secondly, the subboundaries were separated because of the slips of a/a boundaries; and finally, the splitting boundaries were further globularized.
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