新型生物醫(yī)用Mg-Dy-Sr-Nd-Zr合金及其壓鑄態(tài)的組織與性能研究
發(fā)布時間：2019-06-02 05:20
【摘要】：生物鎂合金材料憑借其良好的生物相容性、力學相容性及生物可降解性,受到醫(yī)學界及材料界的廣泛關注,但是降解過程的控制及精密成型等難題限制了其在醫(yī)療領域的臨床應用。近年來,稀土元素成為生物鎂合金材料在合金化方面的研究熱點,含有稀土的WE43醫(yī)用鎂合金同時具有良好的力學性能及耐腐蝕性能。為了開發(fā)出更能適應人體環(huán)境的生物醫(yī)用鎂合金,在WE43合金的基礎上,替換其中稀土元素,選擇了沒有毒性的稀土元素Dy及生物相容性良好的元素Sr作為合金化元素。利用金屬模澆鑄制備了Mg-xDy-ySr-2.4Nd-0.5Zr(x=2、6、10;y=0.5、1.5、2)合金,通過光學顯微鏡(O M)、掃描電鏡(SEM)、室溫拉伸試驗、電化學及失重實驗分別分析了不同含量的Dy以及Sr元素對生物醫(yī)用鎂合金材料的顯微組織、力學性能以及生物降解性能的影響。針對生物鎂合金塑性差的問題,再對具有良好力學性能及耐腐蝕性能的Mg-10Dy-0.5Sr-2.4Nd-0.5Zr合金采用壓鑄成型工藝,并對比分析鑄態(tài)及壓鑄態(tài)生物醫(yī)用鎂合金的組織與性能之間的內(nèi)在規(guī)律。鑄態(tài)Mg-xDy-ySr-2.4Nd-0.5Zr合金的晶粒呈樹枝狀生長,其平均晶粒尺寸隨著Dy元素含量的增加發(fā)生明顯細化。Sr元素對生物鎂合金的晶粒尺寸細化效果并不明顯,但是過量的Sr元素會增加鎂合金偏聚的傾向。鑄態(tài)合金中第二相由Mg2 Dy、Mg3Dy、Mg17Sr2、Mg12N d相組成并沿著晶界析出。D y元素的增加可以通過固溶強化、細晶強化的作用使鎂合金的力學性能得到提高。然而過量的Sr元素導致鎂合金晶粒分布不均從而產(chǎn)生應力集中,因此鎂合金的力學性能隨著Sr含量的增加反而下降。鑄態(tài)生物醫(yī)用Mg-10Dy-0.5Sr-2.4Nd-0.5Zr合金具有最佳的力學性能,其抗拉強度、屈服強度及延伸率依次為203MPa、128MPa、7.4%。生物醫(yī)用Mg-xDy-ySr-2.4Nd-0.5Zr合金的耐腐蝕性能隨著Dy元素的增加通過細化晶粒得到增強。Mg17Sr2容易與α-Mg相發(fā)生電偶腐蝕,因此鎂合金的腐蝕速率隨著Sr元素含量的增加呈增大的趨勢。鑄態(tài)Mg-10Dy-0.5Sr-2.4Nd-0.5Zr合金在PBS模擬體液中具有最佳的耐腐蝕性能,降解速率為0.58mm/a。壓鑄成型沒有改變Mg-10Dy-0.5Sr-2.4Nd-0.5Zr合金的相組成,但是沿晶界分布的第二相呈細小網(wǎng)格狀分布。壓鑄態(tài)合金的晶粒尺寸明顯細化至18μm,晶粒形態(tài)由樹枝晶向等軸晶轉(zhuǎn)變。晶粒大小不均勻并且合金內(nèi)部的氣孔導致壓鑄態(tài)Mg-10Dy-0.5Sr-2.4N d-0.5Zr合金的強度降低,但是壓鑄態(tài)鎂合金的拉伸斷口出現(xiàn)大量的韌窩和撕裂棱,并且延伸率增加,說明壓鑄態(tài)Mg-10Dy-0.5Sr-2.4Nd-0.5Zr合金的塑性明顯增強,斷裂類型屬于準解理斷裂。因此,壓鑄成型技術改善了生物醫(yī)用鎂合金的塑性變形能力。壓鑄態(tài)鎂合金的腐蝕產(chǎn)物溶解速率大于其修復速率,在鎂合金的腐蝕層中沒有形成穩(wěn)定的Mg(OH)2保護膜,極化曲線同樣表明壓鑄態(tài)鎂合金沒有發(fā)生鈍化行為。因此壓鑄成型降低了Mg-10Dy-0.5Sr-2.4Nd-0.5Zr合金的耐腐蝕性能。壓鑄態(tài)鎂合金的腐蝕類型也發(fā)生了改變,由鑄態(tài)合金的局部點腐蝕轉(zhuǎn)變?yōu)榫鶆蚋g。
[Abstract]:With its good biocompatibility, mechanical compatibility and biodegradability, the biological magnesium alloy material is widely concerned by the medical community and the material world, but the control and precision molding of the degradation process have limited its clinical application in the medical field. In recent years, rare earth elements have become hot spots in the alloying of magnesium alloy materials, and the WE43 medical magnesium alloy containing rare earth has good mechanical properties and corrosion resistance. In order to develop a biological medical magnesium alloy which is more suitable for human environment, the rare earth element is replaced on the basis of the WE43 alloy, and the rare earth element Dy with no toxicity and the element Sr with good biocompatibility are selected as the alloying elements. Mg-xDy-ySr-2.4 Nd-0.5Zr (x = 2,6,10; y = 0.5, 1.5,2) alloy was prepared by metal mold casting, and the microstructure of the biological medical magnesium alloy material was analyzed by optical microscope (O M), scanning electron microscope (SEM), room temperature tensile test, electrochemical and weight loss experiment. And the effect of the mechanical property and the biodegradability. In order to solve the problem of the plastic difference of the biological magnesium alloy, an Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy with good mechanical properties and corrosion resistance is adopted to adopt a die-casting forming process, and the internal law of the microstructure and the property of the as-cast and die-cast biomedical magnesium alloy is compared and analyzed. The grain size of the as-cast Mg-xDy-ySr-2.4 Nd-0.5Zr alloy is dendritic growth, and the average grain size of the as-cast Mg-xDy-ySr-2.4 Nd-0.5Zr alloy is obviously refined with the increase of the content of the Dy element. The effect of Sr element on the grain size refinement of the biological magnesium alloy is not obvious, but the excessive Sr element will increase the tendency of the magnesium alloy to become more and more. The second phase in the as-cast alloy is composed of Mg2 Dy, Mg3Dy, Mg17Sr2 and Mg12Nd and is precipitated along the grain boundary. The increase of the D y element can improve the mechanical properties of the magnesium alloy by solution strengthening and fine grain strengthening. However, the excessive Sr element results in uneven distribution of the grain distribution of the magnesium alloy, and the stress concentration is generated, so the mechanical property of the magnesium alloy decreases with the increase of the Sr content. As-cast biomedical Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy has the best mechanical property, and its tensile strength, yield strength and elongation are 203 MPa,128 MPa and 7.4%. The corrosion resistance of the biomedical Mg-xDy-ySr-2.4 Nd-0.5Zr alloy can be enhanced by refining the crystal grains with the increase of the Dy element. Mg17Sr2 is susceptible to galvanic corrosion with the Mg-Mg phase, so the corrosion rate of the magnesium alloy increases with the increase of Sr element content. As-cast Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy has the best corrosion resistance in the body fluid of PBS, and the degradation rate is 0.58mm/ a. The phase composition of the Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy is not changed in the die-casting process, but the second phase along the grain boundary is distributed in a fine mesh shape. The grain size of the die-cast alloy is obviously thinned to 18 & mu; m, and the grain morphology is changed from the dendritic to the like. The grain size is not uniform and the air holes in the alloy lead to the decrease of the strength of the die-cast Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy, but the tensile fracture of the die-cast magnesium alloy has a large number of dimple and tear edges, and the elongation is increased, indicating that the plasticity of the die-cast Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloy is obviously enhanced, The fracture type belongs to the quasi-cleavage fracture. Therefore, the die-casting technology improves the plastic deformation capacity of the biomedical magnesium alloy. The dissolution rate of the corrosion product of the magnesium alloy in the die-casting state is higher than the repair rate, and the stable Mg (OH)2 protective film is not formed in the corrosion layer of the magnesium alloy, and the polarization curve also shows that the magnesium alloy in the die-casting state has no passivation behavior. And the corrosion resistance of the Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy is reduced. The corrosion type of the magnesium alloy in the die-casting state has also changed, and the local point corrosion of the as-cast alloy is changed into uniform corrosion.
【學位授予單位】：蘭州理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：R318.08;TG146.22;TG249.2
本文編號：2490861
[Abstract]:With its good biocompatibility, mechanical compatibility and biodegradability, the biological magnesium alloy material is widely concerned by the medical community and the material world, but the control and precision molding of the degradation process have limited its clinical application in the medical field. In recent years, rare earth elements have become hot spots in the alloying of magnesium alloy materials, and the WE43 medical magnesium alloy containing rare earth has good mechanical properties and corrosion resistance. In order to develop a biological medical magnesium alloy which is more suitable for human environment, the rare earth element is replaced on the basis of the WE43 alloy, and the rare earth element Dy with no toxicity and the element Sr with good biocompatibility are selected as the alloying elements. Mg-xDy-ySr-2.4 Nd-0.5Zr (x = 2,6,10; y = 0.5, 1.5,2) alloy was prepared by metal mold casting, and the microstructure of the biological medical magnesium alloy material was analyzed by optical microscope (O M), scanning electron microscope (SEM), room temperature tensile test, electrochemical and weight loss experiment. And the effect of the mechanical property and the biodegradability. In order to solve the problem of the plastic difference of the biological magnesium alloy, an Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy with good mechanical properties and corrosion resistance is adopted to adopt a die-casting forming process, and the internal law of the microstructure and the property of the as-cast and die-cast biomedical magnesium alloy is compared and analyzed. The grain size of the as-cast Mg-xDy-ySr-2.4 Nd-0.5Zr alloy is dendritic growth, and the average grain size of the as-cast Mg-xDy-ySr-2.4 Nd-0.5Zr alloy is obviously refined with the increase of the content of the Dy element. The effect of Sr element on the grain size refinement of the biological magnesium alloy is not obvious, but the excessive Sr element will increase the tendency of the magnesium alloy to become more and more. The second phase in the as-cast alloy is composed of Mg2 Dy, Mg3Dy, Mg17Sr2 and Mg12Nd and is precipitated along the grain boundary. The increase of the D y element can improve the mechanical properties of the magnesium alloy by solution strengthening and fine grain strengthening. However, the excessive Sr element results in uneven distribution of the grain distribution of the magnesium alloy, and the stress concentration is generated, so the mechanical property of the magnesium alloy decreases with the increase of the Sr content. As-cast biomedical Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy has the best mechanical property, and its tensile strength, yield strength and elongation are 203 MPa,128 MPa and 7.4%. The corrosion resistance of the biomedical Mg-xDy-ySr-2.4 Nd-0.5Zr alloy can be enhanced by refining the crystal grains with the increase of the Dy element. Mg17Sr2 is susceptible to galvanic corrosion with the Mg-Mg phase, so the corrosion rate of the magnesium alloy increases with the increase of Sr element content. As-cast Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy has the best corrosion resistance in the body fluid of PBS, and the degradation rate is 0.58mm/ a. The phase composition of the Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy is not changed in the die-casting process, but the second phase along the grain boundary is distributed in a fine mesh shape. The grain size of the die-cast alloy is obviously thinned to 18 & mu; m, and the grain morphology is changed from the dendritic to the like. The grain size is not uniform and the air holes in the alloy lead to the decrease of the strength of the die-cast Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy, but the tensile fracture of the die-cast magnesium alloy has a large number of dimple and tear edges, and the elongation is increased, indicating that the plasticity of the die-cast Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloy is obviously enhanced, The fracture type belongs to the quasi-cleavage fracture. Therefore, the die-casting technology improves the plastic deformation capacity of the biomedical magnesium alloy. The dissolution rate of the corrosion product of the magnesium alloy in the die-casting state is higher than the repair rate, and the stable Mg (OH)2 protective film is not formed in the corrosion layer of the magnesium alloy, and the polarization curve also shows that the magnesium alloy in the die-casting state has no passivation behavior. And the corrosion resistance of the Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy is reduced. The corrosion type of the magnesium alloy in the die-casting state has also changed, and the local point corrosion of the as-cast alloy is changed into uniform corrosion.
【學位授予單位】：蘭州理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：R318.08;TG146.22;TG249.2
【參考文獻】
相關期刊論文 前10條
1 馬瑩;郭陽;張忠明;徐春杰;呂振林;;Ca對鑄態(tài)Mg-4Zn合金組織及腐蝕性能的影響[J];材料熱處理學報;2015年01期
2 郁元正;;保溫溫度對AM60B鎂合金壓鑄組織和性能的影響[J];鑄造技術;2015年01期
3 王峰;張峰;劉靜;毛萍莉;劉正;;真空壓鑄對AZ91鎂合金組織及性能的影響[J];鑄造;2015年01期
4 王梔沁;張彬;李德江;Robert FRITZSCH;曾小勤;Hans J.ROVEN;丁文江;;熱處理工藝對高真空壓鑄Mg 8Gd 3Y 0.4Zr鎂合金組織及力學性能的影響(英文)[J];Transactions of Nonferrous Metals Society of China;2014年12期
5 李勝勇;李德江;曾小勤;丁文江;;真空壓鑄Mg-6Gd-3Y-0.5Zr鎂合金的組織與性能(英文)[J];Transactions of Nonferrous Metals Society of China;2014年12期
6 李勝勇;李德江;曾小勤;丁文江;;壓鑄Mg-3Nd-0.2Zn-0.4Zr合金的組織和力學性能研究[J];鑄造;2014年12期
7 彭勃;章曉波;王章忠;;Sr含量對Mg-Nd-Zr合金顯微組織與力學性能的影響[J];金屬熱處理;2014年11期
8 Jing Bai;Lingling Yin;Ye Lu;Yiwei Gan;Feng Xue;Chenglin Chu;Jingli Yan;Kai Yan;Xiaofeng Wan;Zhejun Tang;;Preparation, microstructure and degradation performance of biomedical magnesium alloy fine wires[J];Progress in Natural Science:Materials International;2014年05期
9 于照鵬;王柏樹;熊守美;;壓鑄工藝對AT72鎂合金力學性能的影響[J];特種鑄造及有色合金;2014年04期
10 張興凱;韓偉;鄭玉峰;范德增;;純鎂材表面化學鍍鐵[J];材料保護;2014年04期
相關碩士學位論文 前1條
1 蔡淑華;Mg-Zn-Sr系醫(yī)用鎂合金材料的制備及其性能的研究[D];中南大學;2013年
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