高品质Ti662钛合金棒材的制备及无损检测异常区域剖析

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Abstract：Tomeetthe demandof high-end manufacturing industryfor high-strength Ti662 titaniumalloyrods， this research and development work is carried out.A 3-ton Ti662 alloy ingot with a nominal diameter of ϕ720mm which had undergone three rounds of VAR（Vacuum Arc Remelting）refining，was selected and processed into a bar with dimensions of ϕ103mm×1700mm through a combination of high and low temperature forging with multiple heating cycles. After undergoing STA （Solution Treatment and Aging） treatment， the microstructure and mechanical properties of the bar were evaluated according to the TiO3 standard requirements，and the results showed that all properties of the bar met the standard specifications.Following machining of the bar surface，a 38OM portable flaw detector equipped with a 5P14 probe was used to conduct a 100% ultrasonic inspection of the bar using the contact method.Abnormal waveform and high noise signal were found in the local area of the bar material. Upondissecting these areas and conducting a low-magnification examination，distinct bright spots were observed. Subsequent SEM （Scanning Electron Microscope），EDS （EnergyDispersive Spectroscopy），and HV（Vickers Hardness）analyses were performed on the abnormal areas and the matrix areas using an inverted microscope，scanning electron microscope， and Vickers hardness tester，respectively. The metallographic examination revealed that the microstructure at the bright spots lacked primary a -phase and exhibited typical β -rich segregation. The EDS results indicated that the segregated areas had higher concentrations of V，Fe，and Cu elements，while the concentrationsof Al and Sn elements were normal.The Vickers hardness test resultsshowedthat the hardnessof the segregated areas was lower than that of the normal areas， indicating that the segregation was of the soft type.

Keywords： Ti662 titanium alloy; rods;segregation; ultrasonic testing

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Ti662（Ti-6A1-6V-2Sn-0.5Cu-0.5Fe）是在TC4基础上开发的一种富含β稳定元素的高强度 α+β 型钛合金，因其具有优异的强度、固体耐蚀性、中等焊接和制造能力，所以在航空航天、石油化工、造船、汽车及医药等领域得到了成功的应用[1-5]。（剩余6770字）