钴铬合金义齿选区激光熔化及热处理工艺研究

发布时间：2018-04-29 01:13

  本文选题：选区激光熔化 + 钴铬合金　； 参考：《中北大学》2017年硕士论文

【摘要】：与传统精密铸造工艺相比,选区激光熔化(SLM)技术具有生产周期短、成本低且成型精度高的特点。本文针对SLM成形钴铬合金义齿出现的翘曲变形和成形件比自然牙硬度大等问题,优化了钴铬合金义齿SLM支撑结构、SLM成形工艺和热处理工艺,使SLM成形钴铬合金义齿尺寸精度更高、硬度更接近自然牙。本文主要研究内容如下:研究了 SLM成形钴铬合金支撑结构参数的优化。以成形方向的尺寸变化率和支撑去除难易程度作为测量指标,采用正交试验法,进行多组试验,对比观察,确定最佳支撑结构参数:支撑厚度0.5mm,支撑间距0.6mm,接口界面高度0.3mm,顶部接口界面交叉0.15mm。在该支撑结构参数下,SLM成形方向上(Z轴)尺寸变化率为2.8%,且去除支撑后,支撑面破损小。研究了钴铬合金的SLM成形工艺参数的优化。以成形件的尺寸精度为测量指标,分析了激光功率、扫描速度和扫描间距对SLM成形件尺寸精度的影响,并采用正交试验法,对比观察,确定最佳成形工艺参数:激光功率55W,扫描速度600mm·s 1,扫描间距0.03mm,铺粉厚度40μm。在该成形工艺参数下,SLM成形钴铬合金的平均尺寸变化率为1.53%。研究了热处理对SLM成形钴铬合金硬度的影响。采用最优支撑结构参数和SLM成形工艺参数,打印钴铬合金试样,进行热处理实验,测量试样的硬度值,确定热处理工艺参数:加热温度1000℃,保温时间1h,随炉冷却。在该热处理工艺下,SLM成形钴铬合金的硬度为448.2MPa。观察了 SLM成形件的微观组织并测试其力学性能。针对钴铬合金SLM成形件表面进行了 SEM分析,根据分析结果讨论了钴铬合金SLM成形过程中球化机理,提出了减轻球化现象的工艺方法;对比热处理前后的拉伸性能,延伸率提高了约20%; SLM成形钴铬合金的金瓷结合强度45.9MPa,比铸造钴铬合金的金瓷结合强度大约23%。
[Abstract]:Compared with the traditional precision casting technology, selective laser melting (SLM) technology has the advantages of short production cycle, low cost and high forming accuracy. In this paper, aiming at the problems of warping and hardness of the formed part of cobalt-chromium alloy denture formed by SLM, the forming process and heat treatment technology of the SLM supporting structure of the cobalt-chromium alloy denture are optimized. The SLM-shaped cobalt-chromium alloy dentures have higher dimensional accuracy and hardness closer to natural teeth. The main contents of this paper are as follows: the optimization of the structural parameters of SLM-formed cobalt-chromium alloy is studied. Taking the dimension change rate of forming direction and the difficulty degree of brace removal as the measurement index, the orthogonal test method was used to carry out many groups of experiments, and the comparative observation was made. The optimum structural parameters are determined as follows: support thickness 0.5 mm, support spacing 0.6 mm, interface height 0.3 mm, top interface crossing 0.15 mm. The size change rate of Z axis is 2.8 in the forming direction of SLM under the support structure parameters. After the support is removed, the damage of the support surface is small. The optimization of SLM forming process parameters of cobalt chromium alloy was studied. The effects of laser power, scanning speed and scanning distance on the dimensional accuracy of SLM forming parts are analyzed with the dimension accuracy of forming parts as the measurement index. The orthogonal test method is used to compare and observe the effects of laser power, scanning speed and scanning spacing on the dimensional accuracy of SLM forming parts. The optimum process parameters were determined as follows: laser power 55W, scanning speed 600mm S1, scanning distance 0.03mm, powder laying thickness 40 渭 m. The average size change rate of cobalt chromium alloy formed by SLM is 1.53. The effect of heat treatment on hardness of cobalt chromium alloy formed by SLM was studied. The optimum supporting structure parameters and SLM forming process parameters were used to print the cobalt-chromium alloy samples, the hardness of the samples was measured, and the heat treatment parameters were determined as follows: heating temperature 1000 鈩，

本文编号：1817723