含铜钛合金高温变形行为及其板材组织性能研究

Abstract

Titanium alloys can be used to replace human bones due to its the great comprehensive mechanical properties and biocompatibility.However,the ordinary titanium alloy does not have antibacterial properties,implanted in the human body is likely to cause bacterial infection and failure of surgery.So the development of a new type of titanium alloy with antibacterial capacity has become the current hot spots.Cu element because of its excellent antibacterial properties,the use of a long time and low cost advantages has been widely used.In this paper,Ti-6Al-4V-5Cu alloy and Ti-15Mo-5Cu alloy were selected as the research object.These two kinds of alloy ingots were prepared smelting in ISM.Then to explore their hot deformation behavior and sheet properties.

The results show that the as-cast microstructure of Ti-6Al-4V-5Cu alloy is Widmannstatten structure,and the as-cast Ti-15Mo-5Cu alloy is a singleβ-equiaxed structure.When the temperature is from800℃to900℃and the strain rate is0.01s-1 ~1s-1,the deformation parameters on the two alloys have great influence during the hot deformation process.When the deformation rate is constant,the deformation temperature increases while the peak stress becomes smaller.When the deformation temperature is constant,the deformation rate become faster,the peak stress. Ti-6Al-4V-5Cu alloy has a thermal activation energy of203.55KJ/mol,while the raise together.Activation energy of Ti-15Mo-5Cu alloy is only143.98KJ/mol,The dynamic recrystallization capacity of the Ti-15Mo-5Cu alloy is stronger.

According to the deformation structure of the two alloys,it can be seen that when the dynamic recrystallization does not occur completely,the higher the deformation temperature,the finer the grain.When the deformation temperature is constant,the deformation rate become lower,while the grain size become smaller. When the dynamic recrystallization is complete,the increase of deformation temperature and the decrease of deformation rate all contribute to the growth of grain.The hot deformation mechanism of Ti-6Al-4V-5Cu alloy is dislocation’s slip and climb.The continuous dynamic recrystallization process occurs as follows.As the degree of dynamic recrystallization increases,theαphase changes from lamellar to spherical.The hot deformation mechanism of Ti-15Mo-5Cu alloy is grain boundary slip.Discontinuous dynamic recrystallization process is as follows.First of all,the grain boundary of the“bow”due to the crystal deformation is not uniform. Then the dislocation subgrain boundary and the grain boundary protrusion are directly nucleated to form new grains.After aging treatment of the hot deformed

sample,it can be found that the alloy produces Ti2Cu phase,and the Cu element mainly distributes the remainingβphase and Ti2Cu phase.

The results of multi-step deformation experiments show that the grains in the two-pass deformation are smaller than those in the three-step deformation.The rolling process parameters were worked out,according to the experimental results of multi-pass thermal simulation.After that the machined and mechanical properties of the rolled sheet were tested.The results show that the Ti-6Al-4V-5Cu alloy is composed ofαandβ,and there is only a singleβphase in Ti-15Mo-5Cu alloy. While the Cu element is mainly distributed inβ-transformed structure.The tensile strength of Ti-6Al-4V-5Cu alloy is higher and the elastic modulus of Ti-15Mo-5Cu alloy is lower than that of Ti-6Al-4V-5Cu alloy.Ti-6Al-4V-5Cu alloy has the characteristics of microporous aggregation fracture and cleavage fracture,and the fracture mechanism of Ti-15Mo-5Cu alloy is cleavage fracture.

Keywords:copper-containing titanium alloy,hot deformation,thermal activation energy,alloy microstructure during deformation,plate rolling

摘要...............................................................................................................................I Abstract............................................................................................................................II 第1章绪论 (1)

1.1课题来源及研究的目的和意义 (1)

1.2抗菌材料的研究现状 (2)

1.2.1抗菌材料制备方法的选择 (2)

1.2.2抗菌材料中抗菌元素的选择 (2)

1.2.3抗菌合金的发展过程 (3)

1.3生物医用钛合金的发展过程 (4)

1.4抗菌钛铜合金的国内外研究现状 (6)

1.4.1Cu2+抗菌机理 (6)

1.4.2含Cu量对合金性能影响 (7)

1.4.3钛铜合金抗菌处理方法及Cu相分布 (8)

1.5钛合金的热变形特点 (9)

1.5.1(α+β)型钛合金的热变形特点 (9)

1.5.2β型钛合金的热变形特点 (10)

1.6课题主要研究内容 (10)

第2章实验材料及方法 (12)

2.1合金材料的制备 (12)

2.1.1合金铸锭制备 (12)

2.1.2合金板材轧制 (12)

2.2实验方案和分析测试方法 (12)

2.2.1X射线衍射分析(XRD) (12)

2.2.2光学显微组织分析 (13)

2.2.3扫描电子显微镜(SEM)和能谱(EDS)分析 (13)

2.2.4透射电子显微镜（TEM） (13)

2.2.5电子背散射衍射(EBSD)分析 (13)

2.2.6高温变形热物理模拟试验 (14)

2.2.7室温拉伸实验 (14)

第3章两种合金高温变形行为的研究 (15)

3.1引言 (15)

3.2两种合金的铸态显微组织表征 (15)

3.2.1铸态Ti-6Al-4V-5Cu合金的显微组织表征 (15)

3.2.2铸态Ti-15Mo-5Cu合金的制备及显微组织的表征 (17)

3.3变形参数对Ti-6Al-4V-5Cu合金流变应力的影响 (19)

3.3.1变形温度对Ti-6Al-4V-5Cu合金流变应力的影响 (19)

3.3.2应变速率对Ti-6Al-4V-5Cu合金流变应力的影响 (21)

3.4变形参数对Ti-15Mo-5Cu合金流变应力的影响 (22)

3.4.1变形温度对Ti-15Mo-5Cu合金流变应力的影响 (22)

3.4.2变形速率对Ti-15Mo-5Cu合金流变应力的影响 (24)

3.5两种合金热激活能的计算和本构方程的建立 (26)

3.5.1合金热激活能的计算 (26)

3.5.2本构方程的建立 (31)

3.6本章小结 (34)

第4章变形参数对两种合金变形组织的影响 (36)

4.1引言 (36)

4.2变形参数对Ti-6Al-4V-5Cu合金高温变形组织的影响 (36)

4.3变形参数对Ti-15Mo-5Cu合金高温变形组织的影响 (40)

4.4Ti-6Al-4V-5Cu合金变形组织的EBSD表征 (42)

4.5Ti-15Mo-5Cu合金变形组织的EBSD表征 (48)

4.6两种合金高温变形机理的分析 (52)

4.6.1合金压缩变形的受力特点 (52)

4.6.2Ti-6Al-4V-5Cu合金的高温变形机理 (53)

4.6.3Ti-15Mo-5Cu合金高温变形机理 (55)

4.7两种合金热变形组织中抗菌相的表征 (57)

4.7.1两种合金的固溶时效处理 (57)

4.7.2Ti-6Al-4V-5Cu合金中抗菌相的表征 (57)

4.7.3Ti-15Mo-5Cu合金中抗菌相的表征 (59)

4.8本章小结 (61)

第5章两种合金多步变形行为及板材组织性能研究 (62)

5.1引言 (62)

5.2多道次热变形工艺参数对两种合金显微组织的影响 (62)

5.2.1两种合金多道次热变形试样的制备 (62)

5.2.2Ti-6Al-4V-5Cu合金 (62)

5.2.3Ti-15Mo-5Cu合金 (65)

5.3两种合金板材的制备与显微组织分析 (68)

5.3.1两种合金板材的制备 (68)

5.3.2两种合金板材的显微组织表征 (70)

5.4两种合金的拉伸性能 (74)

5.4.1拉伸性能 (74)

5.4.2两种合金的拉伸断口分析 (75)

5.5小结 (76)

结论 (77)

参考文献 (79)

哈尔滨工业大学学位论文原创性声明和使用权限 (84)

致谢 (85)