深冷处理对齿科纯钛激光焊接焊区性能的影响
发布时间：2018-09-19 07:33
【摘要】：目的： 激光焊接是口腔修复的重要技术,其焊接质量关系修复体成败,研究焊区处理工艺提高其综合性能是口腔修复界多年的努力方向。本研究采用深冷处理方法在模拟口腔环境条件下对焊接试样进行处理,以改善齿科纯钛激光焊接焊区综合性能。通过力学性能测试及分析,优化深冷处理工艺,对比与焊接后未处理及热处理组效果,进行耐腐蚀性能及生物性能的初步研究,探讨深冷处理在口腔修复中的临床应用。 方法： 采用德国Dentaurum生产Comlaser-4型激光焊接机对齿科纯钛进行焊接,试样焊缝长6mm,厚0.5mm。采用体外冷热循环和人工唾液浸泡模拟口腔生理环境。 1.优化深冷处理工艺：将焊接试样随机分为六组,其中四组在液氮温度下分别保温2h、12h、24h、48h,一组为传统的热处理组,一组为未经处理的对照组,通过测试六组试样的抗拉强度、延伸率及显微硬度优化处理工艺,并以此工艺作为下列实验深冷处理组。 2.力学性能评价：将试样分为四组(母材组,深冷母材组,激光焊接组,深冷焊接组),冷热循环1000次后再浸泡于人工唾液中90天后取出,测试其力学性能,观察分析显微组织和断口形貌。 3.疲劳性能评价：模拟口腔生理环境,应用Instron E10000电子动静态万能材料试验机测试深冷处理后焊件的疲劳强度,并与未深冷处理组进行比较,绘制出两条S-N曲线,计算其疲劳特征值,并对疲劳断口进行扫描电镜观察。 4.腐蚀性能及抗菌性能评价：测量四组试样(母材组,深冷母材组,激光焊接组,深冷焊接组)的极化曲线,计算其特征性参数,拟合其在人工唾液中的电化学阻抗谱,并利用扫描电镜观察四组焊件的抗菌情况。 5.摩擦磨损性能评价：使用MMV-1立式万能摩擦磨损实验机测量试样的磨损体积损失量,观察试样表面磨损形貌。 结果： 1.24h深冷处理组的抗拉强度及延伸率比其他各组有大幅度提高,并且其焊区硬度并未大幅降低,力学性能较好。 2.在模拟口腔环境下,纯钛母材的抗拉强度和延伸率经深冷处理后分别提高了6.24%和2.2%,而纯钛激光焊接焊区的抗拉强度和延伸率分别提高了20.82%和150%。母材断口呈韧性断裂,未经深冷处理的焊件断口呈脆性断裂,深冷处理焊件断口呈混合准解理断裂。深冷处理后母材晶粒尺寸明显减小,焊区组织更均匀。 3.在同一应力范围下,深冷处理后纯钛焊件的疲劳循环次数均高于对照组,深冷处理组的疲劳强度特征值△ok为121.884MPa,S-N曲线的斜率m为5.94,均高于未深冷组(97.000MPa,5.40),深冷处理后疲劳强度提高了25.65%。相同的应力下,深冷组层片状二次断裂不如未深冷组明显。深冷组最终断裂面韧窝尺寸较大,呈韧窝断裂,而未深冷组的断面韧窝较少,呈准解理断裂。 4.深冷处理后纯钛激光焊接焊区的击穿电位(Eb)值为0.455V,△E值为1.365V,Rp值为282110Ω·cm2,均高于未深冷处理纯钛焊区(0.047V,0.629V,6654Ω.cm2)。深冷处理后焊区表面细菌粘附量少于未深冷处理组。 5.深冷处理后纯钛激光焊接焊区的磨损体积量小于未深冷组(P0.05),其磨损机制为磨粒磨损,而后者磨损机制主要为粘着磨损同时伴磨粒磨损。结论： 1.纯钛激光焊件的优化深冷处理工艺为：液氮温度(-196℃)下保温24h。 2.模拟口腔环境下,与未深冷处理的焊接组对比,深冷处理提高纯钛焊件抗拉强度及延伸率。同时对焊区拉伸性能的提高也优于母材。 3.深冷处理明显提高纯钛激光焊接焊区的疲劳强度。 4.深冷处理显著提高纯钛焊接焊区的耐腐蚀性能及抗菌性能。 5.深冷处理提高激光焊接焊区的摩擦磨损性能。
[Abstract]:Objective:
Laser welding is an important technique in prosthodontics, and its welding quality is related to the success or failure of prosthodontics. To improve the comprehensive performance of prosthodontics, it has been a long-term endeavor for prosthodontics to study the welding zone treatment technology. The mechanical properties were tested and analyzed to optimize the cryogenic treatment process. The effects of cryogenic treatment on corrosion resistance and biological properties were compared with those of untreated and heat treated groups.
Method:
The dental pure titanium was welded by Comlaser-4 laser welding machine made in Dentaurum, Germany. The weld length of the sample was 6 mm and the thickness was 0.5 mm. The oral physiological environment was simulated by in vitro cold and hot cycling and artificial saliva soaking.
1. Optimizing the cryogenic treatment process: The welded specimens were randomly divided into six groups. Four groups were kept in liquid nitrogen for 2 h, 12 h, 24 h and 48 h, one group was the traditional heat treatment group, the other group was the untreated control group. The tensile strength, elongation and microhardness of the six groups of specimens were tested and optimized. Cryogenic treatment group.
2. Mechanical properties evaluation: The specimens were divided into four groups (base metal group, cryogenic base metal group, laser welding group, cryogenic welding group). After 1000 cycles, the specimens were soaked in artificial saliva for 90 days. The mechanical properties were tested, and the microstructure and fracture morphology were observed and analyzed.
3. Fatigue performance evaluation: The fatigue strength of weldments after cryogenic treatment was tested by Instron E10000 electronic dynamic and static universal material testing machine. Two S-N curves were drawn and their fatigue characteristic values were calculated. The fatigue fracture was observed by scanning electron microscope.
4. Corrosion and antibacterial evaluation: Polarization curves of four groups of samples (base metal group, cryogenic base metal group, laser welding group, cryogenic welding group) were measured, their characteristic parameters were calculated, their electrochemical impedance spectra in artificial saliva were fitted, and their antibacterial properties were observed by scanning electron microscope.
5. Friction and wear performance evaluation: MMV-1 vertical universal friction and wear tester was used to measure the wear volume loss and observe the surface wear morphology.
Result:
The tensile strength and elongation of 1.24 h cryogenic treatment group were much higher than those of other groups, and the hardness of welded zone was not significantly reduced, and the mechanical properties were better.
2. In the simulated oral environment, the tensile strength and elongation of pure titanium base metal increased by 6.24% and 2.2% respectively after cryogenic treatment, while the tensile strength and elongation of pure titanium laser welding zone increased by 20.82% and 150% respectively. The fracture of base metal was ductile fracture, the fracture of weldment without cryogenic treatment was brittle fracture, and the fracture of cryogenic treatment weldment was fracture. Mixed quasi cleavage fracture. After cryogenic treatment, the grain size of parent material decreases obviously, and the microstructure of welding zone is more uniform.
3. In the same stress range, the fatigue cycle times of pure titanium weldments after cryogenic treatment were higher than those of the control group. The characteristic value of fatigue strength of cryogenic treatment group was 121.884 MPa, and the slope of S-N curve was 5.94, which was higher than that of non-cryogenic treatment group (97.000 MPa, 5.40). The fatigue strength of cryogenic treatment group was increased by 25.65% under the same stress. The secondary fracture is less obvious than that of the non-cryogenic group. The final fracture surface dimple size of the cryogenic group is larger, showing dimple fracture, while the fracture surface dimple of the non-cryogenic group is less, showing quasi-cleavage fracture.
4. After cryogenic treatment, the breakdown potential (Eb) value of pure titanium laser welded zone is 0.455V, Delta E value is 1.365V, Rp value is 282110 cm 2, which is higher than that of pure titanium welded zone without cryogenic treatment (0.047V, 0.629V, 6654 cm 2).
5. The wear volume of laser welding zone of pure titanium after cryogenic treatment is smaller than that of non-cryogenic treatment (P 0.05). The wear mechanism is abrasive wear, while the latter is mainly adhesive wear and abrasive wear.
1. the optimum cryogenic treatment process for pure titanium laser weldment is: liquid nitrogen temperature (-196 C) and heat preservation 24h..
2. In the simulated oral environment, compared with the welding group without cryogenic treatment, cryogenic treatment can improve the tensile strength and elongation of pure titanium weldments, and the tensile properties of the welding zone are also better than the base metal.
3. cryogenic treatment obviously improves the fatigue strength of pure titanium laser welded zone.
4. cryogenic treatment can significantly improve the corrosion resistance and antibacterial properties of pure titanium welding zone.
5. cryogenic treatment can improve the friction and wear properties of laser welding area.
【学位授予单位】：天津医科大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R783.6
本文编号：2249458
[Abstract]:Objective:
Laser welding is an important technique in prosthodontics, and its welding quality is related to the success or failure of prosthodontics. To improve the comprehensive performance of prosthodontics, it has been a long-term endeavor for prosthodontics to study the welding zone treatment technology. The mechanical properties were tested and analyzed to optimize the cryogenic treatment process. The effects of cryogenic treatment on corrosion resistance and biological properties were compared with those of untreated and heat treated groups.
Method:
The dental pure titanium was welded by Comlaser-4 laser welding machine made in Dentaurum, Germany. The weld length of the sample was 6 mm and the thickness was 0.5 mm. The oral physiological environment was simulated by in vitro cold and hot cycling and artificial saliva soaking.
1. Optimizing the cryogenic treatment process: The welded specimens were randomly divided into six groups. Four groups were kept in liquid nitrogen for 2 h, 12 h, 24 h and 48 h, one group was the traditional heat treatment group, the other group was the untreated control group. The tensile strength, elongation and microhardness of the six groups of specimens were tested and optimized. Cryogenic treatment group.
2. Mechanical properties evaluation: The specimens were divided into four groups (base metal group, cryogenic base metal group, laser welding group, cryogenic welding group). After 1000 cycles, the specimens were soaked in artificial saliva for 90 days. The mechanical properties were tested, and the microstructure and fracture morphology were observed and analyzed.
3. Fatigue performance evaluation: The fatigue strength of weldments after cryogenic treatment was tested by Instron E10000 electronic dynamic and static universal material testing machine. Two S-N curves were drawn and their fatigue characteristic values were calculated. The fatigue fracture was observed by scanning electron microscope.
4. Corrosion and antibacterial evaluation: Polarization curves of four groups of samples (base metal group, cryogenic base metal group, laser welding group, cryogenic welding group) were measured, their characteristic parameters were calculated, their electrochemical impedance spectra in artificial saliva were fitted, and their antibacterial properties were observed by scanning electron microscope.
5. Friction and wear performance evaluation: MMV-1 vertical universal friction and wear tester was used to measure the wear volume loss and observe the surface wear morphology.
Result:
The tensile strength and elongation of 1.24 h cryogenic treatment group were much higher than those of other groups, and the hardness of welded zone was not significantly reduced, and the mechanical properties were better.
2. In the simulated oral environment, the tensile strength and elongation of pure titanium base metal increased by 6.24% and 2.2% respectively after cryogenic treatment, while the tensile strength and elongation of pure titanium laser welding zone increased by 20.82% and 150% respectively. The fracture of base metal was ductile fracture, the fracture of weldment without cryogenic treatment was brittle fracture, and the fracture of cryogenic treatment weldment was fracture. Mixed quasi cleavage fracture. After cryogenic treatment, the grain size of parent material decreases obviously, and the microstructure of welding zone is more uniform.
3. In the same stress range, the fatigue cycle times of pure titanium weldments after cryogenic treatment were higher than those of the control group. The characteristic value of fatigue strength of cryogenic treatment group was 121.884 MPa, and the slope of S-N curve was 5.94, which was higher than that of non-cryogenic treatment group (97.000 MPa, 5.40). The fatigue strength of cryogenic treatment group was increased by 25.65% under the same stress. The secondary fracture is less obvious than that of the non-cryogenic group. The final fracture surface dimple size of the cryogenic group is larger, showing dimple fracture, while the fracture surface dimple of the non-cryogenic group is less, showing quasi-cleavage fracture.
4. After cryogenic treatment, the breakdown potential (Eb) value of pure titanium laser welded zone is 0.455V, Delta E value is 1.365V, Rp value is 282110 cm 2, which is higher than that of pure titanium welded zone without cryogenic treatment (0.047V, 0.629V, 6654 cm 2).
5. The wear volume of laser welding zone of pure titanium after cryogenic treatment is smaller than that of non-cryogenic treatment (P 0.05). The wear mechanism is abrasive wear, while the latter is mainly adhesive wear and abrasive wear.
1. the optimum cryogenic treatment process for pure titanium laser weldment is: liquid nitrogen temperature (-196 C) and heat preservation 24h..
2. In the simulated oral environment, compared with the welding group without cryogenic treatment, cryogenic treatment can improve the tensile strength and elongation of pure titanium weldments, and the tensile properties of the welding zone are also better than the base metal.
3. cryogenic treatment obviously improves the fatigue strength of pure titanium laser welded zone.
4. cryogenic treatment can significantly improve the corrosion resistance and antibacterial properties of pure titanium welding zone.
5. cryogenic treatment can improve the friction and wear properties of laser welding area.
【学位授予单位】：天津医科大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R783.6
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