纯镁丝材拉拔工艺及在模拟体液中的腐蚀行为研究
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摘要
镁具有很高的比刚度和比强度,良好的散热性能、减振性能和电磁屏蔽性能等优良的综合性能,因而在航空航天、汽车以及3C产品领域有广阔的应用前景。由于镁在室温下的塑性变形能力较差,因此有关镁及其合金丝材拉拔变形的研究很少,但是丝材在国民经济中却发挥着重要作用。镁及其合金作为现有金属生物材料的新一代产品所表现出了优势与潜力,根据镁的耐蚀性能较差的特点,有望将其发展成为生物医用可消溶植入材料及器件。
针对镁的这些特点本文研究了纯镁丝材的室温冷拉拔和中高温退火工艺过程,并将得到的丝材在模拟体液中进行腐蚀实验,研究了生理环境和晶粒尺寸对纯镁丝材的腐蚀影响。分析了挤压制坯过程中的挤压参数对丝材拉拔中显微组织和力学性能的影响,摸索最佳挤压工艺为后续的拉拔奠定理论基础;分析了拉拔中显微组织的演变和力学性能的变化情况,同时初步探索了退火工艺对丝材组织的影响,摸索最佳拉拔-退火工艺。还分析了纯镁丝材在不同模拟体液中的腐蚀行为、不同晶粒尺寸的丝材在相同模拟体液中的腐蚀行为以及腐蚀后丝材的表面形貌和力学性能。
拉拔-退火工艺研究发现,丝材的抗拉强度、延伸率随着挤压温度的升高先增大后逐渐减小,挤压温度为100℃的丝材力学性能明显高于室温和200℃的丝材;细化晶粒可以提高丝材强度和硬度,当丝材晶粒达到5~6μm时,抗拉强度可达到238.7MPa,延伸率可达到17.68%;随着冷变形程度的增加丝材的加工硬化效果明显,变形程度达到94.24%时硬度达到73.14HV。
腐蚀实验研究发现,纯镁的腐蚀与生物环境的化学成分及浓度有关,在Hank’s人工模拟体液中腐蚀较缓慢,在生理盐水中腐蚀相对较快,且浓度的增加加速腐蚀;细化晶粒可以减缓腐蚀速率,晶粒5~6μm的丝材在0.9% NaCI生理盐水中腐蚀120h的平均腐蚀速率可降到1.64mm/a;丝材表面发生了点蚀,腐蚀的程度及蚀坑大小与腐蚀液的化学成分及浓度有关。
Magnesium has wide application prospect in the area of aerospace, automotive, and 3C products because of its good properties such as high stiffness/density and strength/density ratio, excellent capacities of heat dissipation, damping and electromagnetic shielding. However, due to magnesium has poor workability at room temperature, now the investigations of magnesium and its alloys wires are very few, But the applications of magnesium wires are very important in national products. Magnesium and its alloys, as a new generation of biological materials, exhibit the exciting potentiality and attractive more and more poeple’s attention. Due to the poor corrosion rates, magnesium alloys are promising in degradable prosthetic implants.
Consider for these characteristics of magnesium, there are some studies about cold drawing and mid-annealing techniques was performed on pure magnesium wires in this paper. Meanwhile, through corrosion tests of magnesium wires in simulated body fluid, the impact factors of PHysical environment and the grain size of pure magnesium affecting on the corrosion of pure magnesium wires were made out. By analysis of the extrusion parameters affecting on the microstructure and mechanical properties in wires drawing, the best extrusion process for follow-up drawing was established. By analysis of evolution of the microstructure and changes of the mechanical properties in drawing, the best drawing - annealing process was found out. Also analyzed the corrosion behavior of pure magnesium wires in different simulated body fluid , and the behavior of wires in different grain size but in the same simulated body fluid as well as the surface morPHology and mechanical properties of wires after corrosion.
By the study of drawing– annealing process, the tensile strength and elongation of wires increased with the extrusion temperature at first then gradually decreased. At the extrusion temperature of 100℃, the mechanical properties of wires was significantly higher than it at the room temperature and the temperature of 200℃. Grain refinement can improve the strength and hardness of wires, When the grain size of wires reached 5 ~ 6μm, the tensile strength can be achieved 238.7MPa, elongation up to 17.68%. With increasing of cold deformation, The work-hardening of wires become effectively. The degree of deformation can be reached 94.24% when the hardness reached 73.14HV.
By the study of corrosion tests, the corrosion of pure magnesium is related to the chemical compsition and concentration of the biological environment. In Hank's artificial simulated body fluid, the corrosion rate was slow, but its became faster in the saline. And increasing of the concentration can accelerate the corrosion rate. Grain refinement can slow down the rate., the average corrosion rate of wires which the grain size is 5~6μm can be reduced to 1.64mm/a in the 0.9% NaCI saline in 120h. The surface of the wires occurred pitting, the extent of corrosion and the size of pit are related to the chemical composition and the concentration of the etching solution
针对镁的这些特点本文研究了纯镁丝材的室温冷拉拔和中高温退火工艺过程,并将得到的丝材在模拟体液中进行腐蚀实验,研究了生理环境和晶粒尺寸对纯镁丝材的腐蚀影响。分析了挤压制坯过程中的挤压参数对丝材拉拔中显微组织和力学性能的影响,摸索最佳挤压工艺为后续的拉拔奠定理论基础;分析了拉拔中显微组织的演变和力学性能的变化情况,同时初步探索了退火工艺对丝材组织的影响,摸索最佳拉拔-退火工艺。还分析了纯镁丝材在不同模拟体液中的腐蚀行为、不同晶粒尺寸的丝材在相同模拟体液中的腐蚀行为以及腐蚀后丝材的表面形貌和力学性能。
拉拔-退火工艺研究发现,丝材的抗拉强度、延伸率随着挤压温度的升高先增大后逐渐减小,挤压温度为100℃的丝材力学性能明显高于室温和200℃的丝材;细化晶粒可以提高丝材强度和硬度,当丝材晶粒达到5~6μm时,抗拉强度可达到238.7MPa,延伸率可达到17.68%;随着冷变形程度的增加丝材的加工硬化效果明显,变形程度达到94.24%时硬度达到73.14HV。
腐蚀实验研究发现,纯镁的腐蚀与生物环境的化学成分及浓度有关,在Hank’s人工模拟体液中腐蚀较缓慢,在生理盐水中腐蚀相对较快,且浓度的增加加速腐蚀;细化晶粒可以减缓腐蚀速率,晶粒5~6μm的丝材在0.9% NaCI生理盐水中腐蚀120h的平均腐蚀速率可降到1.64mm/a;丝材表面发生了点蚀,腐蚀的程度及蚀坑大小与腐蚀液的化学成分及浓度有关。
Magnesium has wide application prospect in the area of aerospace, automotive, and 3C products because of its good properties such as high stiffness/density and strength/density ratio, excellent capacities of heat dissipation, damping and electromagnetic shielding. However, due to magnesium has poor workability at room temperature, now the investigations of magnesium and its alloys wires are very few, But the applications of magnesium wires are very important in national products. Magnesium and its alloys, as a new generation of biological materials, exhibit the exciting potentiality and attractive more and more poeple’s attention. Due to the poor corrosion rates, magnesium alloys are promising in degradable prosthetic implants.
Consider for these characteristics of magnesium, there are some studies about cold drawing and mid-annealing techniques was performed on pure magnesium wires in this paper. Meanwhile, through corrosion tests of magnesium wires in simulated body fluid, the impact factors of PHysical environment and the grain size of pure magnesium affecting on the corrosion of pure magnesium wires were made out. By analysis of the extrusion parameters affecting on the microstructure and mechanical properties in wires drawing, the best extrusion process for follow-up drawing was established. By analysis of evolution of the microstructure and changes of the mechanical properties in drawing, the best drawing - annealing process was found out. Also analyzed the corrosion behavior of pure magnesium wires in different simulated body fluid , and the behavior of wires in different grain size but in the same simulated body fluid as well as the surface morPHology and mechanical properties of wires after corrosion.
By the study of drawing– annealing process, the tensile strength and elongation of wires increased with the extrusion temperature at first then gradually decreased. At the extrusion temperature of 100℃, the mechanical properties of wires was significantly higher than it at the room temperature and the temperature of 200℃. Grain refinement can improve the strength and hardness of wires, When the grain size of wires reached 5 ~ 6μm, the tensile strength can be achieved 238.7MPa, elongation up to 17.68%. With increasing of cold deformation, The work-hardening of wires become effectively. The degree of deformation can be reached 94.24% when the hardness reached 73.14HV.
By the study of corrosion tests, the corrosion of pure magnesium is related to the chemical compsition and concentration of the biological environment. In Hank's artificial simulated body fluid, the corrosion rate was slow, but its became faster in the saline. And increasing of the concentration can accelerate the corrosion rate. Grain refinement can slow down the rate., the average corrosion rate of wires which the grain size is 5~6μm can be reduced to 1.64mm/a in the 0.9% NaCI saline in 120h. The surface of the wires occurred pitting, the extent of corrosion and the size of pit are related to the chemical composition and the concentration of the etching solution
引文
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30. Serre C M, Papillard M, Chavassieux P, et al. Influence of magnesium substitution on a collagen-apatite biomaterial on the production of a calcifying matrix by human oxteoblasts. J Biomed Mater Res, 1998,42: 626
31. Wen C E, Yamada Y, Shimojima K, et al. Compressibility of porous magnesi- um foam: dependency on porosity and pore size. Mater Lett,2004,58: 357
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2.徐春国.镁合金壳体热挤压成形工艺研究.锻压技术, 2003,(6):10-12
3. Kecker T F. The Renaissance in Magnesium. Adv. Mater.&Proc, 1998,(9):31
4.郑润芬.纯镁及镁合金大气腐蚀和化学氧化工艺研究.大连理工大学博士学位论文, 2007
5. K. Kitazone, E. Sato and K. Kuribayash. International Stress Superplasity in Polycrystaline AZ31 Magnesium Alloy. Scirpta Mater, 2001,(44):2695-2702
6. H. Takuda, T. Yoshii, N. Hatta. Finite-element Analysis of the Formability of a Magnesium-based AZ31 Sheet. Journal of Materials Processing Technology, 1999,(89-90):135-140
7. Hidetoshi Somekawa, Hiroyuki Hosokawa, Hiroyuki Walnanbe, Kenji Higash, Diffusion Bonding in Superplastic Magnesium Alloys, Materials Science and Engineering, 2003, (A339):328-333
8.余琨,黎文献.变形镁合金材料的研究进展.轻合金加工技术, 2001,(7):6-9
9.徐奔. AZ31镁合金丝材拉拔工艺的研究.哈尔滨工业大学硕士学位论文, 2006
10.张阳德,欧阳洋.临床常用生物材料及其应用前景.中国医学工程杂志, 2004,12(5):34-37
11.李世普.生物医用材料导论.武汉工业大学出版社, 2000,55
12.郭学峰,魏建峰,张忠明.镁合金与超高强度镁合金.铸造技术, 2002, 23:133
13.刘振东,范清宇.应力遮挡效应-寻找丢失的钥匙.中华创伤骨科杂志, 2002,4:62
14.高玉苓.镁和镁合金耐蚀性能及纯镁表面镀钛研究.辽宁工程技术大学硕士学位论文, 2006
15. Song Guangling, Andre j Atrens. Wu Xianliang, eta1. Corros Sci, 1998, 40 (10):1769
16. Makar G L, Kruger J. Corrosion of magnesium. Int Mater Rev, 1993, 38 (3):138
17. Hideyuki Kuwahara, Al-Abdullat Yousel, Naoko Mazaki, et al. Precipitation of magnesium apatite on pure magnesium surface during immersing in Han k' ssolution[J]. Mater Trans, 2001,42(7):1317
18. Sampath T S, Manjubala Ietal. Synthesis of carbonated calcium PHosPHate ceramics using microwave irradiation. Biomaterials, 2000,21(6):1623
19. Heuer A H, Fink D J, Laraia V J, et al. Innovative materials processing strategiesa biomimetic approach. Science, 1992,255:1098
20.周海涛,曾小勤. AZ31镁合金型材挤压工艺和组织性能分析.轻合金加工技术, 2003, 31(9):28-30
21.黄光胜,汪凌云.镁合金挤压材的组织演变.轻合金加工技术, 2004,(9):35– 37
22.李保成,张星,张冶民.镁合金温变形后的组织与性能.兵器材料科学与工程, 2004,27(6):4-7
23.曲家惠,李四军,张正贵.挤出和退火工艺对AZ31镁合金组织和织构的影向.中国有色金属学报, 2007,17(3):5-6
24.晁红颖. AZ31镁合金的冷拉拔及退火工艺研究.哈尔滨工业大学硕士学位论文, 2007:12-15
25.河望部.引拔加工きれたマネツウム合金ワイヤの特性.轻金属,2004,(11):478
26. Heublein B, Rohde R, Kaese V, et al. Bioeorrosion of magnesium alloys: a new prineiple in cardiovascular implant technology. Heart,2003,89:651
27. Frank Witte, Jens Fischer, Jens Nellesen, et al. In vitro and in vivo corrosion measurements of magnesium alloys. Biomaterial,2006,9:1728
28. Zartner P, Cesnjevar R, Singer H, et al. First successful implantation of a biodegradable metal stent into the left pulmonary artery of a preterm baby. Catheterization and Cardiovascular Interventions,2005,66:590
29. Erbel R, Mario C D, Bartunek J, et al. Ternporary seaffolding of coronary arteries with bioabsorbable magnesiurn stents:a prospective, non-randomised multicentretrial. Lancet, 2007,369:1869
30. Serre C M, Papillard M, Chavassieux P, et al. Influence of magnesium substitution on a collagen-apatite biomaterial on the production of a calcifying matrix by human oxteoblasts. J Biomed Mater Res, 1998,42: 626
31. Wen C E, Yamada Y, Shimojima K, et al. Compressibility of porous magnesi- um foam: dependency on porosity and pore size. Mater Lett,2004,58: 357
32. Witte F, Crostackl H A, Nellesenl J, et al. Characterization of degradable magnesium alloys as orthopaedic implant material by synchrotron-radiation- based microtomograPHy. http: //www.hasylab.desy.de /science/annual reports/ 2001 _report/partl/contrib/47/5461.pdf
33. Dyugulu O, Kaya R A, Oktay G, et al. Investigatlon on the potential of magnesium alloy AZ31 as a bone implant. Mater Sci Forum, 2007,546-549:421
34. Denkena B, Witte F, Podolsky C, et al. Degradable implants made of mag- nesiurn alloys. Proc. of 5th Euspen International Conference, Montpellier, France, 2005
35.席文君,唐凤凰,何昕等.烧结工艺和掺杂对羟基磷灰石陶瓷性能的影响.功能材料, 1996,27(3):274
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