Ti-xCr-yCu钛基材料的制备及组织性能研究

通过粉末冶金法制备了Ti-xCr、Ti-yCu及Ti-xCr-yCu钛基材料,研究了Cr、Cu含量对其相组成、显微组织、压缩屈服强度、弹性模量以及切削加工性能的影响规律。结果表明:随Cr含量的增加,Ti-xCr钛基材料依次出现了Ti_4Cr、TiCr_2及Cr相,其压缩屈服强度表现出先增大后减小的趋势,当Cr含量为10%时其屈服强度达到最大值(710 MPa),同时,添加Cr元素有利于降低钛基材料的弹性模量,最低可达25 GPa。添加Cu元素的钛基材料,随Cu含量的增加,Ti_2Cu相增加,并且显微组织细化,屈服强度降低;弹性模量受Cu含量影响较小而受烧结温度影响较大。添加Cr和Cu元素的钛基材料,其显微组织主要为网篮组织,弹性模量低于纯钛,其中添加Cu元素有利于细化层片,添加Cr元素有利于细化等轴组织。此外,Cr含量为5%时,钛基材料具有较佳的切削加工性能。

Preparation,Microstructure and Mechanical Properties of Ti-xCr-yCu Titanium Based Materials

The Ti-xCr,Ti-yCu and Ti-xCr-yCu titanium based materials were prepared by powder metallurgy using the blended elemental technique. The effects of Cr and Cu additions on phase composition,microstructure,compressive yield strength and elastic modulus were investigated. The results show that with the increase of Cr content,Ti_4Cr,TiCr_2 and Cr phases appeared successively in Ti-x Cr alloys,and the compressive yield strength increases firstly and then decreases. The highest compressive yield strength is 710 MPa when x = 10. In the meantime,the elastic modulus of Ti-xCr alloys decreases and the lowest value is 25 GPa. In Ti-yCu alloys,the precipitated phase( Ti_2Cu) increases,the microstructure gets fine,and the yield strength decreases with the increasing of Cu content. The elastic modulus is less affected by the Cu content and is more affected by the sintering temperature. The microstructure of the titanium based materials containing Cr and Cu,in which Cu is favorable for layer refinement and Cr is favorable for equiaxed microstructure refinement,are mainly basketweave structure,and their elastic moduli are lower than that of pure titanium. The results also show that the machinability of Ti-5 Cr titanium material is better.