本文選題：生物鎂合金　切入點：力學性能　出處：《江西理工大學》2017年碩士論文

【摘要】：生物鎂合金作為新一代人體植入材料近年來備受全球研究者的關注。研究發(fā)現(xiàn),將鎂合金植入人體內(nèi),鎂合金會自然降解,以此避免二次手術對人體造成的傷害和費用,另外自然降解產(chǎn)生的鎂離子既無毒副作用和刺激性,在人體也無排斥和不良現(xiàn)象。相反還會參于人體新陳代謝,多余的鎂離子會被排除體外。相比已經(jīng)廣泛應用于臨床的鈦合金,316L不銹鋼、鈷鉻基合金等,生物鎂合金具有生物安全性、可降解性以及與人體最接近的密度和彈性模量等優(yōu)點,但鎂合金的易被腐蝕和力學性能不高,一直是阻礙其廣泛應用的關鍵問題。本論文的研究工作主要是以合金化為主,加入Sr、Zr、Sn、Ca等元素,再對合金進行軋制,擠壓,熱處理等工藝,改善生物鎂合金的力學性能和耐腐蝕性能,主要的結論如下:1、軋制態(tài)鎂合金主要包括α-Mg為基體,偏析的富Zr區(qū)以及Mg17Sr2,CaMgSn等組成。Zr、Sr、Ca、Sn等元素都能細化組織提高耐腐蝕性能和力學性能,但研究發(fā)現(xiàn),根據(jù)Mg-Zr二元相圖,Zr在液態(tài)鎂中最大的固溶度為0.6%,雖然由于Ca元素的添加對增加Zr的固溶度有積極意義但結合本次實驗結果,Zr的添加不宜大于1%,同樣Sr含量對合金的性能呈現(xiàn)先增后減的現(xiàn)象,結合5組鎂合金的組織性能分析合金元素Sr的加入量控制在1.5-3 wt.%之間比較合適。2、耐腐蝕性能的強弱是由晶粒尺寸和第二相的含量以及分布共同決定的。合金5(Mg-1.5Sr-0.5Sn-0.5Ca)的晶粒尺寸不是最小的,耐腐蝕性能卻是最優(yōu)(其中alloy5合金的抗拉強度為180Mpa,抗壓強度能達到340Mpa,析氫腐蝕速率為0.68 ml/(cm2 day))。因此,探究鎂合金中第二相分布規(guī)律和機理對鎂合金的性能的提高有積極意義。3、擠壓加工后獲得的宏觀組織結構和軋制加工有些類似,并且在均勻化退火后組織變得更加均勻。當保溫溫度確定時,保溫時間是影響組織的重要因素之一,擠壓后對Mg-xSr-yZr-z Sn-0.5Ca進行均勻化退火,當溫度為450℃時,保溫時間不宜超過12小時。4、鎂合金的腐蝕一般以局部腐蝕(特別是點蝕)和晶界腐蝕為主,alloy1的SEM可以看到,在富Zr的晶界處附近,有被腐蝕留下的孔隙,由塔菲爾曲線擬合得知alloy1合金的腐蝕速率為3.29(mm/year),alloy1合金經(jīng)過均勻化退火處理后的抗壓強度提高了68%,達到510Mpa。
[Abstract]:Biomagnesium alloys, as a new generation of human body implant materials, have attracted worldwide attention in recent years. It has been found that magnesium alloys naturally degrade when magnesium alloys are implanted into human bodies, thereby avoiding the harm and cost of secondary surgery. In addition, the magnesium ions produced by natural degradation have neither toxic side effects nor irritation, no rejection or adverse phenomena in the human body. On the contrary, they are also involved in the metabolism of the human body. Superfluous magnesium ions will be excluded from the body. Compared with titanium alloy 316L stainless steel, cobalt-chromium base alloy and so on, biotic magnesium alloys have the advantages of biological safety, biodegradability, density and elastic modulus closest to human body, etc. However, the corrosion and mechanical properties of magnesium alloys are not high, which is the key problem that hinders their wide application. In this paper, alloying is the main research work, and then the alloy is rolled, extruded, heat treated and so on. To improve the mechanical properties and corrosion resistance of biological magnesium alloys, the main conclusions are as follows: (1) rolled magnesium alloys mainly include 偽 -Mg as matrix, Zr-rich segregation and mg _ (17) Sr _ (2) O ~ (2 +) CaMgSn, and other elements, such as .Zr17Sr _ (2) C _ (2) C _ (2) Ca _ (Sn) and so on, can refine the microstructure to improve the corrosion resistance and mechanical properties. But the study found that. According to the Mg-Zr binary phase diagram, the maximum solid solubility of Zr in liquid magnesium is 0.6. Although the addition of Ca has a positive effect on increasing the solubility of Zr, the addition of Zr should not be greater than 1 according to the results of this experiment. The performance of the system increases first and then decreases, Analysis of Microstructure and Properties of 5 groups of magnesium Alloys the addition of Sr in the range of 1.5-3 wt.% is suitable. The corrosion resistance is determined by the grain size and the content and distribution of the second phase. The alloy 5Mg-1.5Sr-0.5Sn-0.5Ca). The grain size is not the smallest. The corrosion resistance of alloy5 alloy is the best. The tensile strength, compressive strength and hydrogen evolution rate of alloy5 alloy are 180MPA, 340Mpaand 0.68 ml/(cm2, respectively. The investigation of the distribution law and mechanism of the second phase in magnesium alloy has positive significance for improving the properties of magnesium alloy. The macrostructure obtained by extrusion processing is similar to that obtained by rolling processing. When the holding temperature is determined, the holding time is one of the important factors affecting the microstructure. After extrusion, the Mg-xSr-yZr-z Sn-0.5Ca is homogenized and annealed at 450 鈩，

本文編號：1656544