本文選題：選區(qū)激光熔化 + GH4169合金�。� 參考：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：選區(qū)激光熔化(SLM)屬于增材制造領(lǐng)域中的一種先進(jìn)技術(shù),在汽車航空等領(lǐng)域應(yīng)用前景廣泛。它可以制造近終端、終端成形件,但是其成形件表面質(zhì)量和致密度一直很難達(dá)到理想狀態(tài)。本課題以GH4169合金為成形材料,以改善SLM成形件表面質(zhì)量和致密度為目標(biāo),系統(tǒng)的研究了工藝參數(shù)對(duì)于它們的影響。通過(guò)設(shè)計(jì)正交實(shí)驗(yàn)方案,首先分別研究各個(gè)工藝參數(shù)對(duì)于樣品表面質(zhì)量和致密度的影響,進(jìn)而將各工藝參數(shù)結(jié)合在一起,研究能量輸入對(duì)于結(jié)果的影響,最后對(duì)成形件上表面粗糙度和致密度的相互影響關(guān)系進(jìn)行分析。同時(shí)對(duì)于粉末未熔、過(guò)熔、粘附、球化等表面缺陷以及孔洞、未熔合、裂紋等內(nèi)部缺陷進(jìn)行了研究。對(duì)于SLM成形件上表面質(zhì)量和致密度的研究結(jié)果表明,成形件上表面質(zhì)量和其致密度主要受到激光功率、掃描速度和掃描間距的影響,而掃描方式對(duì)其影響較小。最優(yōu)工藝參數(shù)組合為激光功率大小為320~340 w,掃描速度大小為1000~1200mm/s,掃描間距大小為60μm,鋪粉層厚大小為40μm,掃描方式旋轉(zhuǎn)角大小為67°。此時(shí)表面粗糙度較小,致密度較高。綜合考慮各個(gè)影響因素可以得出體能量密度在130 J/mm3~150 J/mm3,搭接率在30~40%時(shí),試樣上表面質(zhì)量較好,致密度較高。對(duì)于側(cè)表面的研究結(jié)果表明,側(cè)表面主要受到激光功率的影響,在激光功率為300 w時(shí)成形件側(cè)表面質(zhì)量較好。側(cè)表面質(zhì)量隨著側(cè)面傾斜角度的減小而變差,當(dāng)傾斜角為30°時(shí),側(cè)面出現(xiàn)無(wú)法熔合的現(xiàn)象。且同一工藝參數(shù)下,成形件上表面質(zhì)量要普遍好于側(cè)表面質(zhì)量,側(cè)表面Ra值要比上面Ra值平均高出2.97μm。對(duì)比分析上表面質(zhì)量和致密度,從體能量密度和搭接率兩個(gè)角度進(jìn)行研究,發(fā)現(xiàn)成形件上表面質(zhì)量和致密度相互影響,且表面粗糙度Ra值和致密度呈現(xiàn)負(fù)相關(guān)的規(guī)律。
[Abstract]:Selective Laser melting (SLM) is an advanced technology in the field of material augmentation, which has a wide application prospect in automotive aviation and other fields. It can produce near-end and end-shaped parts, but the surface quality and density of the forming parts are always difficult to reach the ideal state. Taking GH4169 alloy as forming material and improving surface quality and density of SLM forming parts, the influence of process parameters on them is systematically studied in this paper. Through the design of orthogonal experiment scheme, the effects of each process parameter on the surface quality and density of the sample were studied respectively, and then the influence of energy input on the result was studied by combining the process parameters together. Finally, the relationship between surface roughness and density is analyzed. At the same time, the surface defects, such as non-melting, overmelting, adhesion and spheroidization, as well as internal defects such as cavity, unfused, crack and so on, were studied. The results show that the surface quality and density of SLM are mainly affected by laser power, scanning speed and scanning distance, but the scanning mode has little effect on it. The optimum technological parameters are as follows: laser power is 320,340 ws, scanning speed is 1000 ~ 1200mm / s, scanning distance is 60 渭 m, thickness of powder layer is 40 渭 m, rotation angle of scanning mode is 67 擄. The surface roughness is smaller and the density is higher. When the bulk energy density is 130 J/mm3~150 J / mm 3 and the lap ratio is 30 ~ 40 mm, the surface quality of the sample is better and the density is higher. The results show that the side surface is mainly affected by laser power and the surface quality is good when the laser power is 300 w. The surface quality of the side becomes worse with the decrease of the angle of the side slope. When the angle of inclination is 30 擄, the side surface will not fuse. Under the same process parameters, the surface quality of the formed part is generally better than that of the side surface, and the Ra value of the side surface is 2.97 渭 m higher than that of the upper surface. By comparing and analyzing the upper surface quality and density, from the aspects of bulk energy density and lap ratio, it is found that the surface quality and density of the formed parts interact with each other, and there is a negative correlation between the surface roughness Ra value and the density.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG665
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本文編號(hào)：1887097