β型Zr-Mo-Ti合金的显微组织与力学性能

Microstructure and mechanical properties of β type Zr-Mo-Ti alloy

通过真空电弧熔炼炉制备了铸态的Zr-7.5Mo-x Ti（x=0,2,4,8,16 at%）合金,选用光学显微（OM）,X-射线衍射仪（XRD）,压缩试验对试验合金的显微组织及力学性能进行了研究。结果表明：铸态Zr-7.5Mo合金为单一的β相,随着Ti含量的增加,合金中并未出现新的物相,但衍射峰向大角度偏移,这是由于原子半径较小Ti原子溶入Zr中,形成无限固溶体,使合金的晶格间距减小所致。当Ti含量低于4%时,随着Ti含量增加,β晶粒明显细化;当Ti含量大于4%时,随着Ti含量增加,β晶粒反而粗化;Ti含量为4%时,合金的β晶粒尺寸最小,组织均匀,合金的压缩屈服强度最高,约877 MPa,同时合金硬度也最高。所有合金的弹性模量较低,在33～48 GPa之间,且弹性比功较高,能够承受较大的弹性变形。

As-cast Zr-7. 5 Mo-x Ti（ x = 0,2,4,8,16 at%） alloys were prepared in an electric arc melting furnace under vacuum atmosphere. Microstructure and mechanical properties of the tested alloys were investigated by means of optical microscope（ OM）,X-ray diffractometry（ XRD） and compression test. The results show that single β phase is formed in the Zr-7. 5 Mo alloy. With the increasing of Ti content,no other phases are obtained,but the diffraction peaks shift to high angle. The reason is that Ti with small atomic radius and Zr form the infinite solid solution,leading to the decreasing of lattice distance. When the content of Ti is under 4%,the β grain of the tested alloys are obviously refined with the increasing of Ti content. The β phase grain coarsening are very clearly as Ti content is added exceeding 4%.The minimum and the uniform β grain are obtained when Ti content is 4%,and its yield strength is the highest,about 877 MPa. Meanwhile,hardness value of the tested alloys reaches the maximum. In addition,the elastic modulus of all alloys is very lower,ranging from 33 GPa to48 GPa. The high elastic energy indicates that the tested alloys can withstand a greater elastic deformation.