Castro Morgana G, Araújo Cleudmar A, Menegaz Gabriela L, Silva João Paulo L, Nóbilo Mauro Antônio A, Simamoto Júnior Paulo Cézar
Professor, Technical School of Health, Federal University of Uberlândia, Minas Gerais, Brazil.
Professor and Coordinator of the Mechanical Project Laboratory (LPM), Mechanical Engineering School, Federal University of Uberlândia, Minas Gerais, Brazil.
J Prosthet Dent. 2015 May;113(5):460-6. doi: 10.1016/j.prosdent.2014.10.008. Epub 2015 Mar 4.
The literature provides limited information regarding the performance of Ti-6Al-4V laser and plasma joints welded in prefabricated bars in dental applications.
The purpose of this study was to evaluate the mechanical strength of different diameters of Ti-6Al-4V alloy welded with laser and plasma techniques.
Forty-five dumbbell-shaped rods were created from Ti-6Al-4V and divided into 9 groups (n=5): a control group with 3-mm and intact bars; groups PL2.5, PL3, PL4, and PL5 (specimens with 2.5-, 3-, 4-, and 5-mm diameters welded with plasma); and groups L2.5, L3, L4, and L5 (specimens with 2.5-, 3-, 4-, and 5-mm diameters welded with laser). The specimens were tested for ultimate tensile strength (UTS), and elongation percentages (EP) were obtained. Fractured specimens were analyzed by stereomicroscopy, and welded area percentages (WAP) were calculated. Images were made with scanning electron microscopy. In the initial analysis, the data were analyzed with a 2-way ANOVA (2×4) and the Tukey Honestly Significant Difference (HSD) test. In the second analysis, the UTS and EP data were analyzed with 1-way ANOVA, and the Dunnett test was used to compare the 4 experimental groups with the control group (α=.05). The Pearson and Spearman correlation coefficient tests were applied to correlate the study factors. Finite element models were developed in a workbench environment with boundary conditions simulating those of a tensile test.
The 2-way ANOVA showed that the factors welding type and diameter were significant for the UTS and WAP values. However, the interaction between them was not significant. The 1-way ANOVA showed statistically significant differences among the groups for UTS, WAP, and EP values. The Dunnett test showed that all the tested groups had lower UTS and EP values than the control group. The 2.5- and 3-mm diameter groups showed higher values for UTS and WAP than the other test groups. A positive correlation was found between welded area percentage and UTS and a negative correlation between these parameters and the diameters of the specimens. No statistically significant difference was found between the weld techniques.
Under the experimental conditions described, diameters of 2.5 and 3 mm resulted in higher UTS and WAP for both laser and plasma welding and appear to be the best option for joining prefabricated rods in this kind of union.
关于牙科应用中预制棒材上焊接的Ti-6Al-4V激光焊接接头和等离子焊接接头的性能，文献提供的信息有限。
本研究的目的是评估采用激光和等离子技术焊接的不同直径Ti-6Al-4V合金的机械强度。
用Ti-6Al-4V制作45根哑铃形棒材，并分为9组（n = 5）：一个对照组，包含3 mm的完整棒材；PL2.5、PL3、PL4和PL5组（直径为2.5、3、4和5 mm的棒材采用等离子焊接）；以及L2.5、L3、L4和L5组（直径为2.5、3、4和5 mm的棒材采用激光焊接）。对试样进行极限抗拉强度（UTS）测试，并得出伸长率百分比（EP）。通过体视显微镜分析断裂的试样，并计算焊接面积百分比（WAP）。用扫描电子显微镜拍摄图像。在初始分析中，数据采用双向方差分析（2×4）和Tukey真实显著差异（HSD）检验进行分析。在第二次分析中，UTS和EP数据采用单向方差分析进行分析，Dunnett检验用于将4个实验组与对照组进行比较（α = 0.05）。应用Pearson和Spearman相关系数检验来关联研究因素。在工作台环境中开发有限元模型，其边界条件模拟拉伸试验的边界条件。
双向方差分析表明，焊接类型和直径这两个因素对UTS和WAP值具有显著影响。然而，它们之间的相互作用并不显著。单向方差分析表明，各组之间在UTS、WAP和EP值方面存在统计学上的显著差异。Dunnett检验表明，所有测试组的UTS和EP值均低于对照组。直径为2.5和3 mm的组在UTS和WAP方面的值高于其他测试组。发现焊接面积百分比与UTS之间呈正相关，这些参数与试样直径之间呈负相关。两种焊接技术之间未发现统计学上的显著差异。
在所描述的实验条件下，直径为2.5和3 mm的棒材在激光焊接和等离子焊接中均导致更高的UTS和WAP，似乎是在这种连接方式中连接预制棒材的最佳选择。
