摘要
为了研究钛合金薄壁型材的热拉伸变形行为,采用INSTRON高温拉伸实验机对OT4合金薄壁型材的板形拉伸试样进行热拉伸实验,获得了该合金型材在室温至600℃范围内的拉伸实验数据。分析了OT4合金薄壁型材的热拉伸变形规律,并在此基础上建立了其热拉伸变形的Johnson-Cook本构模型。采用相关性系数(R)和平均相对误差(AARE)对本构模型的预测能力进行评估,并对预测数据与实验数据之间偏差产生的原因进行了分析。结果表明,300℃及以下温度范围内,本构模型的应力预测值与实验值吻合度较好;但随着温度的升高,应力预测值与实验值之间偏差明显增大,导致模型的平均相对误差较高(值为4.3392%)。为了提高应力预测值与实验值之间的吻合度,本文对Johnson-Cook本构模型中相对温度与应力之间的关系进行修正,修正后的平均相对误差值降至2.0994%。
In order to study the hot tensile deformation behavior of titanium alloy thin wall section, the hot tensile tests of OT4 alloy thin wall section were conducted on INSTRON high temperature tensile machine.Then, the tensile test data of the alloy from room temperature to 600 ℃ were obtained. The hot tensile deformation regulation of OT4 alloy thin wall section was analyzed. Then, the Johnson-Cook constitutive model for hot tesile deformation was established. Both of the correlation coefficient(R) and average absolute relative error(AARE) were used to evaluate the predictive ability of the constitutive model. The reasons of the deviation between predictive data and test data were analyzed. The results show that the stress data obtained by the constitutive model is well close to test data at the low temperatures(≤300 ℃). But, the difference value between predictive data and test data increases with the increase of temperature,which can lead to a higher AARE value(4.3392%). In order to improve the goodness fit of predictive data and test data, the relationship between stress and relative temperature in Johnson-Cook model was amended, and then the AARE value of the amended constitutive model decreases to2.0994%.
引文
[1]黄张洪,曲恒磊,邓超,等.航空用钛及钛合金的发展及应用[J].材料导报,2011,25(1):102-107.
[2]张宝柱,孙洁琼.钛合金在典型民用飞机结构上的应用现状[J].航空工程进展,2014,5(3):275-281.
[3]邓同生,李尚,卢娇,等.钛合金型材精密挤压技术国内外研究现状[J].锻压技术,2018(6):1-9.
[4]马忠贤,冯军宁,胡志杰.钛及钛合金型材研究进展[J].世界有色金属,2016(12):52-53.
[5]张君峰,徐哲,冯红超.热处理工艺对Ti-6Al-4V钛合金热挤压型材组织及力学性能的影响[J].世界有色金属,2018(2):10-12.
[6]Liu R,Melkote S,Pucha R,et al.An enhanced constitutive material model for machining of Ti-6Al-4V alloy[J].Journal of Materials Processing Technology,2013,213(12):2238-2246.
[7]肖军杰,李东升,李小强,等.钛合金薄壁零件数控热拉伸蠕变复合成形研究进展[J].稀有金属材料与工程,2013,42(12):2629-2634.
[8]王玲,董恩国,武大伟.钛合金型材拉弯模具仿真分析于优化[J].沈阳航空航天大学学报,2015,32(5):54-58.
[9]Peng J,Zhou C Y,Dai Q,et al.An improved constitutive description of tensile behavior for CP-Ti at ambient and intermediate temperatures[J].Materials and Design,2013,50:968-976.
[10]Li X Q,Guo G Q,Xiao J,et al.Constitutive modeling and the effects of strain-rate and temperature on the formability of Ti-6Al-4V alloy sheet[J].Materials and Design,2014,55:325-334.
[11]Ghavam M H,Morakabati M,Abbasi S M,et al.Flow behavior modeling of IMI834 titanium alloy during hot tensile deformation[J].Transactions of Nonferrous Metals Society of China,2015,25(3):748-758.
[12]Fu P F,Hu F Y,Ay C,et al.The welding technology and the microstructure of TC2 alloy by Nd:YAG laser[J].China Surface Engineering,2011,24(6):87-91.
[13]Kotkunde N,Deole A D,Gupta A K,et al.Comparative study of constitutive modeling for Ti-6Al-4V alloy at low strain rates and elevated temperatures[J].Materials and Design,2014,55:99-1005.
[14]Wang F Z,Zhao J,Zhu N,et al.A comparative study on Johnson-Cook constitutive modeling for Ti-6Al-4V alloy using automated ball indentation(ABI)technique[J].Journal of Alloys and Compounds,2015,633(5):220-228.
[15]Moc ko W,Adam B.Application of opticalfield analysis of tensile tests for calibration of the Rusinek-Klepaczko constitutive relation of Ti6Al4V titanium alloy[J].Materials and Design,2015,88(25):320-330.
[16]Cai J,Li F G,Liu T Y,et al.Constitutive equations for elevated temperature flow stress of Ti-6Al-4V alloy considering the effect of strain[J].Materials and Design,2011,32:1144-1151.
[17]Li J,Li F G,Cai J,et al.Comparative investigation on the modified Zerilli-Armstrong model and Arrhenius-type model to predict the elevated-temperature flow behaviour of 7050aluminium alloy[J].Computational Materials Science,2013,71:56-65.