为了研究铝合金7075-T651的流变应力变化特征,在高温分离式霍普金森压杆装置上对圆柱试样进行了温度范围25~400℃及应变率范围600~12000 s?1的动态压缩试验.结果表明:铝合金7075-T651的流变应力对应变率不敏感,对温度有较强的敏感性.总体上,流变应力随温度的升高而减小,但在350~400℃时流变应力差别很小.在高应变速率时,当应变超过一定水平时,应力出现急剧减小,材料发生失效.通过变形后试样的微观组织观察可以发现,应变速率较高时出现绝热剪切带是材料流变应力急剧减小的主要原因.在实验数据基础上,建立了一个基于物理概念的铝合金7075-T651本构模型预测其流变应力,与实验对比表明,所建立的本构模型在较宽的温度和应变速率范围内能够很好地预测铝合金7075-T651的流变应力.
@@@@To understand the flow stress characteristics of aluminum 7075-T651, dynamic compression tests during the temperature range of 25?400℃and strain rate range of 600?12 000 s?1 were performed on cylindrical samples using SHPB technique. The results show that the flow stress of aluminum 7075-T651 is strongly sensitive to temperature compared with strain rate, the flow stress reduces with the increase of temperature. There is a temperature range between 350?400℃where the flow stress doesn’t depend on temperature, showing little difference. At high strain rate when the strain exceeds one certain level, the flow stress decreases sharply and the sample fails. Through the observation of cross-section microstructure of deformed sample, the shear band is responsible for the rapid reduction of flow stress. Finally based on experimental data, a physically based constitutive model is given to depict the flow stress of the aluminum. The model predictions are compared with the results of experiments. Good agreement between the theoretical predictions and experimental results is obtained. The given constitutive model can predict the flow stress of aluminum 7075-T651 in a wide range of temperatures and strain rates.
参考文献
| [1] | 毕运波,柯映林,董辉跃.航空铝合金薄壁件加工变形有限元仿真与分析[J].浙江大学学报（工学版）,2008(03):397-402. |
| [2] | 张洪伟,张以都,赵晓慈,吴琼.航空结构件加工变形仿真关键技术[J].北京航空航天大学学报,2008(02):239-243,248. |
| [3] | 付秀丽,艾兴,万熠,张松.铝合金7050高温流变应力特征及本构方程[J].武汉理工大学学报,2006(12):113-116. |
| [4] | 赵寿根,何著,杨嘉陵,程伟.几种航空铝材动态力学性能实验[J].北京航空航天大学学报,2007(08):982-985. |
| [5] | 李娜,李玉龙,郭伟国.3种铝合金材料动态性能及其温度相关性对比研究[J].航空学报,2008(04):903-908. |
| [6] | 朱耀,庞宝君,邹东利,盖秉政,甄良.7055铝合金动态压缩下的剪切局部化[J].稀有金属材料与工程,2010(z1):159-161. |
| [7] | Woei-Shyan Lee;Wu-Chung Sue;Chi-Feng Lin;Chin-Jyi Wu .The strain rate and temperature dependence of the dynamic impact properties of 7075 aluminum alloy[J].Journal of Materials Processing Technology,2000(1/3):116-122. |
| [8] | Sia Nemat-Nasser;Yulong Li .Flow stress of F.C.C. polycrystals with application to OFHC Cu[J].Acta materialia,1998(2):565-577. |
| [9] | Sia Nemat-Nasser;Wei-Guo Guo;Vitali F. Nesterenko .Dynamic response of conventional and hot isostatically pressed Ti--6Al--4V alloys : experiments and modeling[J].Mechanics of materials,2001(8):425-439. |
| [10] | Sia Nemat-Nasser;Wei-Guo Guo;David P. Kihl .Thermomechanical response of Al-6XN stainless steel over a wide range of strain rates and temperatures[J].Journal of the Mechanics and Physics of Solids,2001(8):1823-1846. |
| [11] | Sia Nemat-Nasser;Wei-Guo Guo .Thermomechanical response of DH-36 structural steel over a wide range of strain rates and temperatures[J].Mechanics of materials,2003(11):1023-1047. |
| [12] | Sia Nemat-Nasser;Wei-Guo Guo .Thermomechanical response of HSLA-65 steel plates: experiments and modeling[J].Mechanics of materials,2005(2/3):379-405. |
| [13] | 郭伟国.4种新型舰艇钢的塑性流变应力及其本构模型[J].金属学报,2006(05):463-468. |
| [14] | 郭伟国.锻造钽的性能及动态流动本构关系[J].稀有金属材料与工程,2007(01):23-27. |
| [15] | 郭伟国,田宏伟.几种典型铝合金应变率敏感性及其塑性流动本构模型[J].中国有色金属学报,2009(01):56-61. |
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