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目的探讨国产纯钛和Ti-6Al-4V合金的铸造性能。方法本研究于2012年9—12月在大连市口腔医院和大连理工大学完成。选择国产纯钛与Ti-6Al-4V合金为2个处理组,进口纯钛为对照组。制作规格为20 mm×20 mm×0.76 mm、具有7×6格栅网的网状蜡型18个;制作直径3.5 mm、长度10 mm的棒状蜡型6个。将2种蜡型随机分配到2个处理组和1个对照组中,每组网状蜡型6个,棒状蜡型2个。所有蜡型经包埋、焙烧、铸造过程最终得到相应的铸件。分别从铸件表面性状、铸流率、内部气孔情况、表面反应层情况等方面评价国产纯钛、Ti-6Al-4V合金与进口纯钛铸造性能的差异。结果 (1)表面性状:进口纯钛组网状铸件表面均无残缺不全,没有缩孔、粘砂及铸造缺陷现象,外观为银灰色;国产纯钛组有2个网状试件表面结构不够完整,Ti-6Al-4V合金组有1个网状试件结构不够完整,所有试件均无缩孔,无明显粘砂,表面呈银灰色。(2)铸流率:国产纯钛、Ti-6Al-4V合金和进口纯钛3种钛材在同等条件下的铸流率分别为95%、94%和100%,进口纯钛比国产纯钛和Ti-6Al-4V合金的铸流率高,差异有统计学意义(χ2=9.28,P<0.05)。(3)内部气孔:X线检查显示,国产纯钛、Ti-6Al-4V合金和进口纯钛3种钛材铸件的内部均有少量小气孔,且都位于铸件的远心端,其大小和数量无明显差别。(4)表面反应层:3种钛材铸件在500倍扫描电镜(SEM)下观察,均可见表面存在大量孔隙,微观结构较为疏松,放大2000倍后可发现大量相互交错的孔隙,形态不规则;表面反应层主要成分线分析结果均显示在表层显微组织结构中除了Ti元素以外,有其他杂质元素存在;表面显微硬度值均随着测量深度的增加而逐渐降低,直至慢慢平缓,提示铸件表面硬度较内部硬度高。结论国产纯钛和Ti-6Al-4V合金的铸流率与进口纯钛有差异,但均符合临床使用的要求。二者铸件内部气孔和表面反应层情况与进口纯钛近似。国产纯钛和Ti-6Al-4V合金在铸造性能方面可以应用于临床。
Objective To investigate the casting properties of domestic pure titanium and Ti-6Al-4V alloy. Methods The study was performed in Dalian Dental Hospital and Dalian University of Technology from September to December in 2012. Choose domestic pure titanium and Ti-6Al-4V alloy as two treatment groups, import pure titanium as control group. Production specifications for the 20 mm × 20 mm × 0.76 mm, with 7 × 6 grid mesh 18 reticular wax; production diameter of 3.5 mm, length of 10 mm rod-shaped wax 6. Two types of wax were randomly assigned to two treatment groups and one control group, each having 6 reticular waxes and 2 rod-shaped waxes. All wax patterns are embedded, roasted, and the resulting castings are finally cast. The differences of casting properties of domestic pure titanium, Ti-6Al-4V alloy and imported pure titanium were evaluated respectively from casting surface properties, casting flow rate, internal porosity and surface reaction layer conditions. Results (1) The surface properties: Pure titanium group mesh casting surface without incomplete, no shrinkage, sticky sand and casting defects, the appearance of silver gray; domestic pure titanium group 2 mesh specimen surface structure is not enough Intact, Ti-6Al-4V alloy group has a mesh specimen structure is not complete, all samples were no shrinkage, no sticky sand, the surface was silver gray. (2) Casting flow rate: The flow rates of domestic pure titanium, Ti-6Al-4V alloy and imported pure titanium were 95%, 94% and 100% under the same conditions respectively. The casting flow rate of titanium and Ti-6Al-4V alloy was high, the difference was statistically significant (χ2 = 9.28, P <0.05). (3) internal porosity: X-ray examination showed that the domestic titanium, Ti-6Al-4V alloy and titanium imports of three kinds of titanium castings have small amounts of internal pores, and are located at the telecentric end of the casting, the size and No significant difference in the number. (4) The surface reaction layer: The three kinds of titanium castings were observed under 500 times scanning electron microscope (SEM), there are a large number of pores on the surface, the microstructure is more loose, after 2000 times magnification can be found a large number of mutually staggered pores, irregular shape The results of the main compositional analysis of the surface reaction layer all showed that in addition to the Ti element, there were other impurity elements in the microstructure of the surface layer. The surface microhardness values gradually decreased with the increase of the measurement depth, Tip casting surface hardness higher than the internal hardness. Conclusion The casting flow rate of domestic pure titanium and Ti-6Al-4V alloy is different from that of imported pure titanium, but all meet the requirements of clinical use. Both the internal porosity of the casting and the surface reaction layer is similar to the imported pure titanium. Domestic titanium and Ti-6Al-4V alloy in casting performance can be applied to clinical.