The Effects Of Deformation Process Parameters On Microstructure And Mechanical Properties Of TA2and TC4Titanium Alloy

Titanium and titanium alloys were used in the aerospace industry, since entering the newcentury. However, the old deformation technology can not adapt to the shape deformation oftitanium sheet, the sheet severe cracking during forming process and parts processed causedeformation more easily. Applications of titanium alloys were limited for a long time. Thedeformation process of titanium alloy was investigated in order to improve these deficiencies.In this paper, a series of experiments were conducted for TA2, TC4titanium alloy in state keylaboratory of rolling and automation (Northeastern University). The effects of deformationprocess parameters on microstructure and mechanical properties of TA2and TC4titaniumalloy were studied systematacially. The main work and research results are as follows:(1) The TC4titanium alloy made thermal phase transition experiments. The researchobtains TC4titanium alloy (α+β)/β phase transition temperature range of952.5℃. Thecooling rates affect (α+β)/β phase transition temperature. The differences of the phasetransition temperature increase with decreasing cooling rate. The microstructure wasobserved under different cooling rates of the sample shows that inhibit the growth of α phaseof the cooling rate is too large.(2) The TA2, TC4titanium alloy made thermal simulation experiments. The paperstudied the ways of cooling, deformation temperature, the amount of deformation, strain rate,cooling temperature and other factors determined by microstructure and mechanicalproperties changes in titanium alloys. The results obtain deformation process parameters onmicrostructure and properties of titanium affected are significantly high amount ofdeformation. High strain rate and other parameters are increased titanium stress-strain andhardness values. Observation of the microstructure, TC4titanium alloy at850℃have betterorganized, most small microstructure especially when the deformation temperature of850℃.TA2titanium appeared lath organization when the deformation temperature of900℃.(3) TC4titanium alloy made cupping experiment. The results shows that TC4titaniumalloy heat treated in different aging process under the cupping value is different, When theprocess of temperature is530℃, time is1hour, the cupping value of3.30mm is minimum.The process of temperature is480℃, time is6hour, the cupping value of5.20mm ismaximum. (4) TA2titanium in cupping value under different heat treatment processes are different.When the experimental program is directly rolled to a thickness of1mm, then varying theannealing treatment. The cupping value is maximum (9.21mm). When the experimentalprogram is the first rolled to a thickness of4mm and then rolled to a thickness of about1mm.The cupping value is minimum (3.95mm).The investigation of effects of deformation process parameters on microstructure andmechanical properties of TA2and TC4titanium alloy not only can improve the relationshipbetween used titanium processing technology and microstructure and mechanical propertiesof TA2, TC4titanium alloy, but also can have a guidance for deformation processing of theTA2and TC4titanium alloy.