新型Zr-Ti基合金制备与组织性能研究

论文总字数：33471字

摘 要

Zr合金因其具有无毒性、良好的力学性能和生物相容性，近年来成为生物医用金属材料研究的热点。本文利用金相显微镜、万能试验机、显微硬度计、扫描电镜、电化学工作站等设备，探究了不同Zr、Ti、Nb含量合金的物相组成、力学性能和耐腐蚀性能，期望设计出符合生物医用标准的新型Zr合金。

金相图片和XRD结果表明Zr-(20, 35, 50)Ti二元合金在铸态和固溶态完全由针状的马氏体α’相组成。随Ti含量增加，马氏体之间逐渐呈平行态，交叉减少，马氏体变细小。Zr-50Ti-(5, 15, 25)Nb三元合金主要由β相组成，其中Zr-50Ti-5Nb合金仍有少许α’相存在，表明Nb是Zr合金的强β稳定元素。

采用显微硬度计和电子万能试验机对六种合金的综合力学性能（主要是硬度、抗压强度、屈服强度和弹性模量）进行了测试。结果表明：随着Ti含量增加，Zr-Ti二元合金的硬度逐渐增大，弹性模量、抗压强度和屈服强度先降后增；随着Nb含量增加，Zr-Ti-Nb三元合金硬度逐渐减小，弹性模量、抗压强度和屈服强度先降后增。Zr-50Ti-15Nb的综合力学性能在六种合金中最优良。

采用电化学工作站对六种合金的耐蚀性进行了测试。结果表明：在以林格溶液为腐蚀介质的模拟环境中，随着Ti含量的增加，合金的开路电位呈逐渐上升趋势；随着Nb含量的增加，开路电位呈先升后降的变化趋势。合金的腐蚀电流、腐蚀电位和钝化电流密度随着Ti含量的增加而增大，随着Nb含量增加逐渐减小，极化曲线的分布规律和开路电位相一致。测试结果表明所有合金的耐蚀性均优于传统Ti合金TC4，且Zr-50Ti-5Nb合金的耐蚀性最优。上述电化学工作站的测试结果与腐蚀前后合金表面形貌的变化规律相吻合。

关键词：Zr合金；β相；力学性能；耐蚀性能；钝化

ABSTRACT

Zirconium alloy has become a hotspot in biomedical metal materials in recent years due to its non-toxicity, good mechanical properties and biocompatibility. In this paper, the phase composition, mechanical properties and corrosion resistance of alloys with different Zr, Ti and Nb contents were investigated by means of metallographic microscope, universal testing machine, microhardness tester, scanning electron microscope and electrochemical workstation, to design a new zirconium alloy for biomedical standards.

The metallographic picture and XRD results show that the Zr-(20, 35, 50) Ti binary alloy consists entirely of acicular martensite α' phase after as-cast and solution treatment. With the Ti content increasing, the martensite becomes parallel and finer, the cross is reduced. The Zr-50Ti-(5, 15, 25) Nb ternary alloy is mainly composed of β phase, and the Zr-50Ti-5Nb alloy still has a little α' phase composition, indicating that Nb is a strong β-stabilizing element of Zr alloy.

The comprehensive mechanical properties (mainly hardness, compressive strength, yield strength and elastic modulus) of six alloys were tested using a microhardness tester and an electronic universal testing machine. The results show that the hardness of Zr-Ti binary alloy increases with the increase of Ti content, and the compressive strength, yield strength and elastic modulus decrease first and then increase. With the increase of Nb content, Zr-Ti-Nb ternary alloy The hardness gradually decreases, and the compressive strength, yield strength, and elastic modulus decrease first and then increase. The comprehensive mechanical properties of Zr-50Ti-15Nb are superior among the six alloys.

The corrosion resistance of the six alloys was tested using an electrochemical workstation. In Ringer's solution, with the increase of Ti content, the open circuit potential of the alloy increases gradually. And the open circuit potential rises firstly and then falls with the increase of Nb content. With the increase of Ti content, the corrosion current, corrosion potential and passivation current density of the alloy increase and with the increase of Nb content，they decrease. The distribution of polarization curve is consistent with that of the open circuit potential. The test results show that the corrosion resistance of all alloys are better than TC4, and the Zr-50Ti-5Nb alloy have the best corrosion resistance. In addition, the surface morphology of the alloy before and after corrosion shows the similar results as the electrochemical workstation test.

Key words: Zirconium alloy; β phase; Mechanical properties; Corrosion resistance; Passivation

目 录

摘要Ⅰ

ABSTRACTⅡ

第一章 绪论1

1.1 生物医用材料1

1.1.1 生物医用材料简介1

1.1.2 生物医用金属材料要求1

1.1.3 目前生物医用金属材料的局限性3

1.2 Zr及Zr合金3

1.2.1 Zr合金研究历史3

1.2.2 合金元素的影响4

1.2.3 热处理制度4

1.2.4 耐腐蚀性5

1.2.5 Zr合金在生物医用上研究进展5

1.3 研究意义及主要内容6

1.3.1 研究意义6

1.3.2 研究主要内容7

第二章 实验方案8

2.1 引言8

2.2 试样制备8

2.2.1 原材料及合金成分8

2.2.2 试样制备过程8

2.3 固溶处理9

2.4 显微组织观察9

2.4.1 金相组织观察9

2.4.2 物相分析9

2.5 力学性能测试10

2.5.1 硬度测试10

2.5.2 压缩测试10

2.5.3 断口扫描10

2.6 腐蚀性能测试10

第三章 实验结果分析12

3.1 引言12

3.2金相组织观察12

3.3 硬度测试14

3.4 力学性能测试15

3.5.1 压缩测试15

3.5.2 断口扫描16

3.5 固溶处理17

3.6 耐蚀性能测试20

第四章 结论24

4.1 实验成果24

4.2 不足与展望24

参考文献26

致谢30

1. 绪论
   1. 生物医用材料

1.1.1生物医用材料简介

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