Al-5Ti-1B合金等通道转角挤压的组织和性能研究

Effects of Equal Channel Angular Pressing on Microstructure and Properties of Al-5Ti-B Alloy

研究了等通道转角挤压技术对Al-5Ti-1B合金的组织和性能的影响。采用等通道转角挤压技术,在室温下,对Al-5Ti-1B合金进行了4道次挤压试验,并运用X射线衍射仪、金相显微镜和扫描电镜等研究形变前后Al-5Ti-1B合金微观结构的变化。结果表明,等通道转角挤压技术可以细化晶粒,改善了第二相颗粒分布的均匀性,提高了Al-5Ti-1B合金的力学性能。随挤压次数的增加,大块状TiAl3相由20～80μm粗晶粒细化到10μm左右;呈团块状且分布不均的TiB2经挤压后,分布均匀。采用Bc路径,进行4道次等通道转角挤压后,Al-5Ti-1B合金的屈服强度由142.0MPa增加到221.4MPa,提高了56.1%,其维氏硬度由45.2增大到64.9,提高了43.6%。

The microstructure of Al-5Ti-1B alloy after equal channel angular pressing with four passes at room temperature was observed by XRD(X-ray diffraction),OM(optical microscope)and SEM(scanning electron microscope).It was found that the equal channel angular pressing can improve the mechanical properties of the alloy as a result of refining the grain size and improving the distributed uniformity of secondary phase in the matrix alloy.With increasing in pass,the bulk TiAl3 phase in alloy can be refined from 20~80 μm to about 10 μm,and the uneven bulk TiB2 can become more uniform.The yield strength and Vickers hardness of Al-5Ti-1B alloy are increased from 142.0 MPa to 221.4 MPa and from 45.2 to 64.9,increased by 56.1% and by 43.6%,respectively,after four passes equal channel angular pressing based on the Bc routes.