本文選題：增材制造　切入點(diǎn)：選區(qū)激光熔化　出處：《蘭州理工大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：與傳統(tǒng)的減材或者等材制造技術(shù)原理不同,增材制造技術(shù)(Additive Manufacturinig,AM)的原理是利用微積分的思想,以添加材料的方式把三維實(shí)體自下而上分層制造,最終完成三維實(shí)體的制造過(guò)程。選區(qū)激光熔化(Selective laser melting,SLM)技術(shù)是金屬材料增材制造技術(shù)的一種。國(guó)產(chǎn)GH4169高溫合金因其具有較好的高溫強(qiáng)度、良好的抗氧化和熱腐蝕性能,而被廣泛應(yīng)用到航空航天等領(lǐng)域。但是由于采用傳統(tǒng)鑄造方法生產(chǎn)GH4169零部件容易出現(xiàn)宏觀偏析及有害的Laves脆性相,鍛造方法對(duì)成型件幾何形狀有要求,因此GH4169高溫合金應(yīng)用受到限制。而利用選區(qū)激光熔化成型工藝生產(chǎn)GH4169解決了以上傳統(tǒng)方法中出現(xiàn)的問(wèn)題。本文通過(guò)對(duì)國(guó)產(chǎn)GH4169合金粉末選區(qū)激光熔化成型工藝進(jìn)行研究,利用單因素變量方法對(duì)成型過(guò)程的參數(shù)(掃描間距、掃描速度、激光功率)進(jìn)行研究,以SLM成型件致密度、表面質(zhì)量及孔洞為衡量指標(biāo),最終得到最佳的成型參數(shù):鋪粉層厚40um,激光光斑大小為100um,基板預(yù)熱80℃,掃描間距為70um,掃描速度為1750~2250mm/s,激光功率為300W~375W。對(duì)成型件組織及性能進(jìn)行分析。分析結(jié)果表明:選區(qū)激光熔化成型件組織主要由尺寸小于0.3um的柱狀晶和胞狀晶組成。柱狀晶粒貫穿多個(gè)熔道呈外延生長(zhǎng),且形成大角度晶界;成型件不同的方位硬度不一致,成型件的拉伸性能優(yōu)于鑄件標(biāo)準(zhǔn)。熱處理可以大幅度提高SLM成型件的硬度及拉伸性能,均達(dá)到鍛件標(biāo)準(zhǔn),成型件熱處理前后的拉伸斷裂模式均為韌性斷裂。
[Abstract]:In contrast to the traditional manufacturing principles of subtractive or isotropic materials, the principle of incremental manufacturing technology is to use the idea of calculus to delaminate three-dimensional entities from bottom to top by adding materials. The selective laser melting laser melting (SLM) technology is a kind of metal material augmentation technology. The domestic GH4169 superalloy has good high temperature strength, good oxidation resistance and hot corrosion resistance. It is widely used in aerospace and other fields. However, because the traditional casting method is easy to produce GH4169 parts with macro segregation and harmful Laves brittle phase, the forging method requires the geometric shape of the molded parts. Therefore, the application of GH4169 superalloy is restricted, and the problems in the traditional methods mentioned above are solved by using the selective laser melting molding process. This paper studies the selective laser melting molding process of domestic GH4169 alloy powder. Single factor variable method was used to study the parameters (scanning distance, scanning speed, laser power) of the molding process. The density, surface quality and porosity of the SLM molded parts were taken as the measurement index. Finally, the best molding parameters are obtained: the thickness of powder layer is 40 ums. the laser spot is 100 um. the substrate is preheated at 80 鈩，

本文編號(hào)：1632019