反复熔铸对钴铬烤瓷合金力学性能影响的研究

目的 探讨反复熔铸对钴铬烤瓷合金力学性能的影响.方法 钴铬烤瓷合金经过单纯反复熔铸3次后,用拉伸实验对各代试件的拉伸强度、0.2%屈服强度、延伸率进行比较;用弯曲实验对各代试件的弯曲强度、弯曲模量进行比较;用硬度实验对各代试件的维氏硬度值进行比较.结果 经过不同熔铸次数的钴铬烤瓷合金的拉伸强度、0.2%屈服强度、延伸率...     

细菌脂多糖对选择性激光熔化技术制作的钴铬钼合金离子析出的影响

目的 通过ICP-MS测定浸泡液中金属离子含量，研究细菌脂多糖（Lipopolysaccharides，LPS）对选择性激光熔化技术（Selective laser melting，SLM）制作的钴铬钼合金离子析出的影响。方法 分别运用SLM技术（SLM组）和传统铸造方法（对照组）制作钴铬钼合金试件支架，每组6个。将每组3个合金试件分别浸泡于单纯人工唾液或加入150 μg/mL LPS的人工唾液中，7日后移除合金试件，用ICPMS方法分析溶液中钴（Co）、铬（Cr）、钼（Mo）3种金属离子的析出量。结果 与单纯人工唾液相比，对照组浸泡于含LPS的人工唾液中的合金试件的Co离子析出量较高（P<0.05），而SLM组在不同溶液中的离子析出量则无明显差异（P>0.05）。无论在含或不含LPS的人工唾液中，SLM组的Co、Mo离子析出量都远远低于对照组（P<0.05）。结论 LPS对SLM制作的钴铬钼合金支架的离子析出量无明显影响。与传统铸造工艺相比，SLM制作的钴铬钼合金支架离子析出量较少。     

Ti—75铸造后机械性能测试的研究

目的：研究及比较Ｔｉ－７５金属在牙科铸造后的机械性能。方法：利用Ｉｎｓｔｒｏｎ拉伸试验机，对Ｔｉ－７５金属牙科铸造后部分力学性能进行了测试研究，并与Ｔｉ－６Ａｌ－４Ｖ及临床常用钴铬合金进行了比较。结果：Ｔｉ－７５铸造后抗拉强度为８５６．７ＭＰａ，屈服强度为５４０ＭＰａ延伸率为７．３％。Ｔｉ－６Ａｌ－４Ｖ铸造后抗拉强度为９５６．７ＭＰａ，屈服强度为５９０ＭＰａ，延伸率为５．２％。Ｃｏ－Ｃｒ合金铸造后抗拉强度为６５１．２ＭＰａ，屈服强度为４７８．８ＭＰａ，延伸率为６．１％。结论：Ｔｉ－７５金属铸造后抗拉强度，屈服强度及延伸率等性能指标均优于钴铬合金，延伸率也高于Ｔｉ－６Ａｌ－４Ｖ合金。     

加工参数设置对选择性激光熔积钴铬合金硬度的影响

目的 观测几种加工参数设置对选择性激光熔积(SLM)钴铬合金的表面形貌和表面维氏硬度的影响。方法 使用正交实验设计9组不同的加工参数,即激光功率为2500W、2750W、3000W,扫描速度为5mm/s、10mm/s、15mm/s,送粉速率为3r/min、4.5r/min、6r/min,制备9组选择性激光熔积钴铬合金试件,每组5个(直径10mm,厚度3mm),经抛光处理后分别进行扫描电镜观察和表面维氏硬度测试,采用SPSS16.0软件包进行数据处理。结果 9组不同加工参数制备下SLM钴铬合金试件的扫描电镜图像均呈现均匀而规则的细胞样结构;其平均表面维氏硬度均在345HV以上。结论 当加工参数设置在激光功率2500~3000W,扫描速度5~15mm/s,送粉速率3~6r/min范围内时, SLM钴铬合金具有较为理想的表面形貌和表面硬度,能适合临床应用需求。     

反复熔铸对金铂烤瓷合金力学性能影响的研究

目的 探讨反复熔铸对金铂烤瓷合金力学性能的影响。方法 金铂烤瓷合金经过单纯反复熔铸3次后,用拉伸实验对各代试件的拉伸强度、0.2%屈服强度、延伸率进行比较;用弯曲实验对各代试件的弯曲强度、弯曲模量进行比较;用硬度实验对各代试件的维氏硬度值进行比较。结果 经过不同熔铸次数的金铂烤瓷合金的拉伸强度、0.2%屈服强度、延伸率、弯曲强度及维氏硬度值差异均无统计学意义。Ⅱ代、Ⅲ代试件的弯曲模量与Ⅰ代相比,显著升高（P<0.05）。结论 金铂烤瓷合金至少可以反复熔铸3次而不引起力学性能的下降。     

牙科用非贵金属高熔铸造合金铸造前后金相比较研究

目的比较牙科用非贵金属高熔铸造合金铸造前后的金相结构。方法应用卧式显微镜观察牙科用非贵金属高熔铸造合金铸造前后的金相结构。结果牙科用非贵金属高熔铸造合金铸造前的金相结构是奥氏体+珠光体+碳化物;软、硬质钴铬合金铸造后金相结构基本不变,而镍铬不锈钢铸造后金相结构呈大量球状物析出状,这可能与合金的化学成份及铸造后处理方法不同有关。结论提示钴铬合金铸造前后性能较镍铬不锈钢稳定。     

牙科用非贵金属高熔铸造合金铸造前后金相比较研究

目的：比较牙科用非贵金属高熔铸造合金铸造前后的金相结构,方法：应用卧式显微镜观察牙科用非贵金属高熔铸造合金铸造前后的金相结构,结果：牙科用非贵金属高熔铸造合金铸造前的金相结构是奥氏体＋珠光体＋碳化物;软、硬质钴铬合金铸造后金相结构基本不同变,而镍铬不锈钢铸造后金相结构呈大量球状物析出状,这可能与合金的化学成份及铸造后处理方法不同有关。结论：提示钴铬合金铸造前后性能较镍铬不锈钢稳定。     

细菌脂多糖对选择性激光熔化技术制作的钴铬钼合金腐蚀行为的影响

目的 研究不同浓度细菌脂多糖（Lipopolysaccharides,LPS）对选择性激光熔化技术（Selective laser melting,SLM）制作的钴铬钼合金腐蚀行为的影响。方法 分别以SLM法及铸造法各制作12个钴铬钼合金试件,根据在腐蚀电解液中LPS浓度（0、0.15、15、150 μg/mL）不同分为4组,每组3个试件。采用电化学阻抗谱、动电位极化测试法分析2组合金试件在不同浓度脂多糖（LPS）中的腐蚀行为。结果 在单纯人工唾液中,SLM合金和铸造合金的腐蚀参数无统计学上的差异（P> 0.05）。当LPS浓度为150 μg/mL时,SLM合金和铸造合金的电阻（R_p）均显著下降且自腐蚀电流密度（I_corr）显著增大,但SLM合金的R_p值大于铸造合金且I_corr值较小（P< 0.05）。结论 LPS对SLM法和铸造法制作的钴铬钼合金的腐蚀行为均有不利影响,但对SLM法制作的合金的腐蚀影响小于铸造法制得的合金。     

不同比例的新旧钴铬合金机械性能的研究

通过比较不同比例的新旧钴铬合金铸造后的抗拉强度,屈服强度,延伸率,硬度等机构性能指标,并结合相应的金相观察及化学成份分析,得出结论;铸造钴铬合金中可加入不超过４０％的仅铸造过一次的旧料而不影响合金的主要机械性能,超过这一比例,将影响修复体的质量。     

钴铬合金废料回收再利用的实验研究（一）——再生型钴铬合金的机械性能测试

通过对已熔铸过并经特殊工艺处理后的齿科钴铬合金与原材料各种机械性能的对比试验，结果表明，回收材料与原材料在硬度、抗拉强度、屈服强度、延伸率、断面收缩率及抗冲击强度等机械性能上无显著差异，证实了齿科钴铬合金回收再利用的可行性     

�����Ͻ����ܸ��Ͻ�Ļ�е���ܼ���ɽ��ǿ�ȱȽ��о�

目的 对比钯银(Pd-Ag)合金和钴铬(Co-Cr)合金的机械性能及金瓷结合强度,为临床提供基础数据.方法 本研究于2010年12月至2011年2月在中国科学院金属研究所分析测试部完成.常规方法制作Pd-Ag合金和Co-Cr合金试件,首先对二者进行硬度测试和拉伸测试,然后分别行常规烤瓷并利用水平剪切法进行界面结合强度测试,利用扫描电镜(SEM)和能谱分析技术对金瓷界面进行观察和元素分析.结果 硬度:Pd-Ag合金为(187.44±3.64) HV,低于Co-Cr合金(361.53±10.15)HV(P＜ 0.05).拉伸测试:Pd-Ag合金的屈服强度为(467.50±14.40)MPa,小于Co-Cr合金(568.10± 30.94) MPa (P＜ 0.05);Pd-Ag合金的抗拉强度为(631.83±15.51)MPa,小于Co-Cr合金(758.73±25.85) MPa(P＜ 0.05).剪切强度:Pd-Ag合金为(57.67±5.44) MPa,Co-Cr合金为(26.80±4.95)MPa,差异有统计学意义(P＜0.05).扫描电镜观察和能谱分析显示:2种合金与瓷之间均存在过渡层,合金与瓷层间存在元素的相互渗透.结论Pd-Ag合金的机械性能低于Co-Cr合金,但可满足临床需要;而Pd-Ag合金的金瓷结合强度高于Co-Cr合金.     

Mechanical properties and microstructures of cast Ti-Cu alloys.

OBJECTIVES: This study evaluated the mechanical properties of cast Ti-Cu alloys with the hope of developing an alloy for dental casting with better mechanical properties than unalloyed titanium. METHODS: Ti-Cu alloys with five concentrations of copper (0.5, 1.0, 2.0, 5.0 and 10.0 mass%) were made in an argon-arc melting furnace. The alloys were cast into magnesia-based molds using a centrifugal casting machine. The microstructure, microhardness profile of the specimen cross section, tensile strength, yield strength, and elongation were determined for the castings. Scanning electron microscope fractography was undertaken for the fractured surfaces after tensile testing. XRD was performed on the polished specimens. Results were analyzed using one-way ANOVA and the Student-Newman-Keuls tests. RESULTS: The mean tensile strengths of all the cast Ti-Cu alloys were significantly (p<0.05) higher than for cast commercially pure titanium (CP Ti). Of the Ti-Cu alloys tested, the 5 and 10% Cu alloys had significantly higher strength than the rest. The 10% Cu alloy exhibited the lowest mean elongation. CP Ti and the 0.5 and 1% Cu alloys showed higher ductility. The bulk hardness of all the cast Ti-Cu alloys, except for the 10% Cu alloy, and CP Ti was approximately the same. SIGNIFICANCE: By alloying with copper, the cast titanium became stronger. Increases in the tensile strength (30%) and yield strength (40%) over CP Ti were obtained for the 5% Cu alloy. Elongation was approximately 3%, which was similar to cast Ti-6Al-4V. Ti-Cu alloys, such as the 5% Cu alloy, could be used for prosthetic dental applications if other properties necessary for dental castings are obtained.     

自制焊丝与商品焊丝对激光焊件机械性能的影响

目的:通过宏观及微观分析焊丝对焊件机械强度的影响,为临床选择焊丝提供依据。方法:采用不同焊丝(自制和商业成品焊丝)对钴铬合金、镍铬合金进行焊接,测定焊件的最大抗拉及抗弯强度,对数据进行单因素方差分析;并通过微观断口扫描电镜观察和熔合区金相分析,探讨焊丝对焊件机械强度的影响。结果:钴铬合金自制焊丝组和商品焊丝组的最大抗拉强度分别为(606.40±82.53)MPa和(693.61±47.68)MPa,最大抗弯强度分别为(997.95±88.89)MPa和(1160.76±91.59)MPa,2组焊件的最大抗拉及抗弯强度均有显著差异(P<0.05);镍铬合金自制焊丝组和商品焊丝组的最大抗拉强度分别为(558.14±46.75)MPa和(582.32±35.43)MPa,最大抗弯强度分别为(1084.75±46.02)MPa和(1078.29±36.25)MPa,2组焊件的最大抗拉及抗弯强度均无显著差异(P>0.05)。断口扫描电镜及熔合区金相分析显示:自制焊丝组焊件的裂纹明显多于商品焊丝组。结论:对力学性能要求较高部位的焊接,应采用商业焊丝。     

异种金属间激光焊接的初步研究

目的:通过对焊件机械强度的测定及熔合区微观结构的分析,探讨口腔常用合金异种金属间激光焊接的可行性。方法:采用钴铬合金、镍铬合金、纯钛进行异种金属间的激光焊接,测定焊件的最大抗拉、抗弯强度,并进行拉伸断口的扫描电镜观察和熔合区的金相分析,探讨激光焊接异种金属的焊接质量及临床应用的可行性。结果:钴铬和镍铬合金异种金属间的激光焊件机械性能较好,钴铬焊丝组和镍铬焊丝组在最大抗拉、抗弯强度上无显著差异(P>0.05)。纯钛与钴铬或者镍铬合金激光熔接接头脆性大,断面可见严重的裂纹和气孔。结论:钴铬合金与镍铬合金异种合金间的激光焊接,不管采用钴铬焊丝或者镍铬焊丝,都可获得良好的焊接接头。纯钛与钴铬合金或者镍铬合金都不能采用激光直接进行熔接     

激光焊接铁铬钼合金与钴铬合金的机械性能

目的：测试激光焊接铁铬钼软磁合金与钴铬合金的机械性能，为临床应用提供参考。方法：采用国产Nd：YANG程控激光焊接机焊接铁铬钼软磁合金与钴铬合金，以激光焊接钴铬合金作为对照。利用Instron万能拉仲实验机测试焊接后的拉仲强度、0．2％屈服强度，作断裂口的扫描电镜分析，并分别进行比较。结果：激光焊接铁铬钼软磁合金与钴铬合金的拉伸强度、0．2％屈服强度与对照组无差别。激光焊接铁铬钼合金与钴铬合金的断裂口呈韧性—解理混合型断裂，而激光焊接钴铬合金的断口呈准解理断裂。结论：激光焊接铁铬钼软磁合金与钴铬合金的机械性能可满足临床需要。     

Superplastic forming of titanium alloy denture base

Ti-6Al-4V alloy has both excellent biocompatibility and superior mechanical properties. This Ti-6Al-4V can be deformed greatly and easily at the superplastic temperature of 800 degrees C to 900 degrees C. The superplastic forming of Ti-6Al-4V was made to apply to fabrication of denture base. Almost the same procedure as for dental casting mold was employed in producing the superplastic forming die by the improved phosphate bonded investment. In the pressure vessel of heat resistant alloy, Ti-6Al-4V plate was formed superplastically on the die by argon gas pressure at 850 degrees C. The fit of superplactic forming Ti-6Al-4V denture base was better than that of casting Co-Cr alloy denture bases. The Ti-6Al-4V alloy might react a little with the die. Because micro Vikers hardness of the cross-section did not go up too much near the surfaces. Even just after being formed, the surfaces were much smoother than that of Co-Cr alloy casting. The tensile strength and yield strength of superplastic forming Ti-6Al-4V were higher than those of Co-Cr castings. The elongation was about 10%. These results show that superplastic forming of Ti-6Al-4V would be suitable for a denture base.     

Fracture strength of porcelain fused to metal crowns made of cast,milled or laser-sintered cobalt-chromium

Abstract

Aims. The aim was to compare the fracture strength of porcelain fused to metal crowns with copings fabricated in Co-Cr using different manufacturing techniques (casting, milling and laser-sintering) with crowns manufactured in a high-gold alloy. Methods. A total of 50 identical crowns were fabricated and sub-divided into five groups; cast Co-Cr, milled Co-Cr, two groups of laser-sintered Co-Cr and a control group cast in a high-gold alloy. After thermocycling (5000 cycles, 5–55°C) and pre-load (30–300 N, 10,000 cycles) the crowns were loaded until fracture. Load (N) and fracture mode were recorded. Results. There was a significant difference (p < 0.05) in fracture strength between the control group and one of the laser-sintered groups. The mean values (N) for the groups were as follows: cast Co-Cr, 1560 ± 274; milled Co-Cr, 1643 ± 153; laser-sintered Co-Cr 1, 1448 ± 168; laser-sintered Co-Cr 2, 1562 ± 72; control group, 1725 ± 220. Conclusion. There is no difference in strength between Co-Cr crowns produced using the different production technologies: casting, milling or laser-sintering. Metal ceramic crowns made with copings fabricated in a high-gold alloy present numerically higher fracture strength than crowns made with copings fabricated in Co-Cr alloys. The difference is confirmed when analyzing the fracture surfaces, but the difference in fracture strength value is limited and is only significant with regard to one of the two laser-sintered groups.     

Mechanical properties and microstructures of dental cast Ti-Ag and Ti-Cu alloys

In this study, experimental Ti-Ag alloys (5, 10, and 20 mass% Ag) and Ti-Cu alloys (2, 5, and 10 mass% Cu) were made in an argon-arc melting furnace. The alloys were cast into magnesia molds using an argon gas-pressure dental casting machine, and the mechanical properties and microstructures of the castings were investigated. As the concentration of silver or copper in the alloys increased, the tensile strength, yield strength, and hardness of the alloys became higher than those of CP Ti, and the elongation of the alloys became lower than that of CP Ti. Changes in the mechanical properties by alloying were considered to be caused by solid-solution strengthening of the a-phases and by precipitation of intermetallic compounds.     

微束等离子弧熔焊和银钎焊钴铬合金机械性能的比较

目的 比较微束等离子弧熔焊和银钎焊钴铬合金的机械性能。方法 采用微束等离子弧焊机熔焊钴铬合金试件,银钎焊法焊接相同规格试件作比较,利用万能拉伸实验机测试两组试件的抗拉强度,观察试件的断裂部位。结果 微束等离子电弧焊试件的抗拉强度大于银钎接试件的抗拉强度,焊接接头的强度接近母材强度,断裂部位在母材和焊缝处的比例为1:1;银钎接试件的抗拉强度较低,有5/6断裂部位在焊缝处。结论 微束等离子弧熔焊钴铬合金机械性能优良,有临床应用前景。