静磁场深冷处理对TC4钛合金性能和组织的影响

Performance and Microstructure of TC4 Titanium Alloy with Static Magnetic Field and Deep Cryogenic Treatment

采用扫描电镜(SEM)、电子背散射衍射(EBSD)和X射线衍射(XRD)检测技术研究了深冷处理(DCT)和静磁场深冷处理(MDCT)条件下TC4钛合金的力学性能和组织的变化。结果表明:在处理时间为12 h的时候DCT和MDCT试样的拉伸性能均为最优,其中DCT12的抗拉强度和延伸率较空白样分别提高了2.6%和8.1%, MDCT12的抗拉强度和延伸率较空白样分别提高了3.00%和11.29%。深冷处理和静磁场深冷处理在TC4钛合金的改性方面都具有一定的效果,且静磁场深冷处理对拉伸性能的提升效果要强于单独的深冷处理。深冷处理使晶粒从(110)转向(100)和(101)方向。施加静磁场后,磁场增加了晶粒向(100)和(101)方向转动的阻力,(002)晶面表现出择优取向。钛合金晶体结构发生变化的原因是晶粒由于冷缩力和磁性附加驱动力的作用。此外,通过EBSD的检测,发现深冷和静磁场深冷处理都促进了钛合金中α→β的转变,且深冷处理弱化了{0001}方向的织构,而静磁场深冷处理强化了该方向的织构。

Scanning electron microscopy(SEM),electron backscatter diffraction(EBSD)and X-ray diffraction(XRD)techniques were combined to investigate the mechanical properties and microstructure of TC4 titanium alloy subjected to sole deep cryogenic treatment(DCT)and simultaneous static magnetic field and deep cryogenic treatment(MDCT).It showed that the DCT and MDCT samples achieved the optimal properties when the processing time was 12 h,and the tensile strength and elongation of the DCT12 sample increased by 2.6%and 8.1%,respectively,compared with that of initial sample,while the tensile strength and elongation of MDCT12 sample increased by 3.00%and 11.29%,respectively.Deep cryogenic treatment and simultaneous static magnetic field and deep cryogenic treatment had certain effect on the modification of TC4 titanium alloy,and the effect of simultaneous static magnetic field and deep cryogenic treatment on tensile properties was stronger than that of cryogenic treatment alone.Deep cryogenic treatment made the(110)plane transform toward(100)and(101).However,after the application of a simultaneous static magnetic field,the magnetic field increased the resistance of grain in(100)and(101)direction,and the(002)crystal plane of MDCT sample showed the preferred orientation.The change of microstructure was attributed to the grain rotation caused by the effect of cold compression force and magnetic driving force.In addition,the EBSD results showed that both of the sole DCT and MDCT promoted the transformation ofα→βin titanium alloy,and sole DCT weakened the texture of{0001}direction,while MDCT strengthened it.