發(fā)布時(shí)間：2018-04-29 01:13

  本文選題：選區(qū)激光熔化 + 鈷鉻合金��； 參考：《中北大學(xué)》2017年碩士論文

【摘要】：與傳統(tǒng)精密鑄造工藝相比,選區(qū)激光熔化(SLM)技術(shù)具有生產(chǎn)周期短、成本低且成型精度高的特點(diǎn)。本文針對(duì)SLM成形鈷鉻合金義齒出現(xiàn)的翹曲變形和成形件比自然牙硬度大等問(wèn)題,優(yōu)化了鈷鉻合金義齒SLM支撐結(jié)構(gòu)、SLM成形工藝和熱處理工藝,使SLM成形鈷鉻合金義齒尺寸精度更高、硬度更接近自然牙。本文主要研究?jī)?nèi)容如下:研究了 SLM成形鈷鉻合金支撐結(jié)構(gòu)參數(shù)的優(yōu)化。以成形方向的尺寸變化率和支撐去除難易程度作為測(cè)量指標(biāo),采用正交試驗(yàn)法,進(jìn)行多組試驗(yàn),對(duì)比觀察,確定最佳支撐結(jié)構(gòu)參數(shù):支撐厚度0.5mm,支撐間距0.6mm,接口界面高度0.3mm,頂部接口界面交叉0.15mm。在該支撐結(jié)構(gòu)參數(shù)下,SLM成形方向上(Z軸)尺寸變化率為2.8%,且去除支撐后,支撐面破損小。研究了鈷鉻合金的SLM成形工藝參數(shù)的優(yōu)化。以成形件的尺寸精度為測(cè)量指標(biāo),分析了激光功率、掃描速度和掃描間距對(duì)SLM成形件尺寸精度的影響,并采用正交試驗(yàn)法,對(duì)比觀察,確定最佳成形工藝參數(shù):激光功率55W,掃描速度600mm·s 1,掃描間距0.03mm,鋪粉厚度40μm。在該成形工藝參數(shù)下,SLM成形鈷鉻合金的平均尺寸變化率為1.53%。研究了熱處理對(duì)SLM成形鈷鉻合金硬度的影響。采用最優(yōu)支撐結(jié)構(gòu)參數(shù)和SLM成形工藝參數(shù),打印鈷鉻合金試樣,進(jìn)行熱處理實(shí)驗(yàn),測(cè)量試樣的硬度值,確定熱處理工藝參數(shù):加熱溫度1000℃,保溫時(shí)間1h,隨爐冷卻。在該熱處理工藝下,SLM成形鈷鉻合金的硬度為448.2MPa。觀察了 SLM成形件的微觀組織并測(cè)試其力學(xué)性能。針對(duì)鈷鉻合金SLM成形件表面進(jìn)行了 SEM分析,根據(jù)分析結(jié)果討論了鈷鉻合金SLM成形過(guò)程中球化機(jī)理,提出了減輕球化現(xiàn)象的工藝方法;對(duì)比熱處理前后的拉伸性能,延伸率提高了約20%; SLM成形鈷鉻合金的金瓷結(jié)合強(qiáng)度45.9MPa,比鑄造鈷鉻合金的金瓷結(jié)合強(qiáng)度大約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，

本文編號(hào)：1817723