【摘要】：選擇性激光熔化技術(shù)(SLM)作為一種新興的增材制造技術(shù),正受到越來越多的關(guān)注。選擇性激光熔化鋁合金的強(qiáng)度較傳統(tǒng)鑄造工藝有了很大的提升。但目前關(guān)于SLM AlSi10Mg合金的成型性能還有待深入研究。本論文使用選擇性激光熔化技術(shù)制備了AlSi10Mg合金成型件,利用X射線衍射(XRD)、金相顯微鏡、掃描電鏡、顯微硬度計和拉伸試驗機(jī)等設(shè)備,分析了SLM工藝參數(shù)和熱處理工藝對成型件的組織結(jié)構(gòu)、表面粗糙度、致密度及力學(xué)性能的影響。結(jié)果表明:(1)試驗用Al Si10Mg合金粉末粒徑分布大部分在5-45μm之間。SLM粉末平均粒徑并非越小越好,粉末粒徑在10μm以下會很容易被保護(hù)氣體吹起,懸浮在成型腔內(nèi),這部分粉末會對激光束造成散射,干擾激光能量的正常輸出,同時減少空氣過濾系統(tǒng)的使用壽命。因此在粉末粒徑的配比上,可以減少使用粒徑在10μm以下的粉末。(2)選擇性激光熔化Al Si10Mg合金成形件的微觀形貌在激光掃描垂直截面上呈魚鱗狀,在平行激光掃描方向的面上觀察呈長條狀。微觀組織為Si呈環(huán)島狀分布在Al的基體中,并將Al基體分割為一個個小島狀。(3)小功率180 W,激光掃描速度為800-1 000 mm/s時,試樣的內(nèi)部孔洞缺陷隨著掃描速度增加而增加。重熔可以增加成型件的致密度減少孔洞缺陷。致密度增加了4.15%,抗拉強(qiáng)度增加23.21%。(4)相同熱輸入,高功率高掃描速度下的成型件比低功率低掃描速度具有更高的強(qiáng)度。激光功率為320 W,在掃描速度為1 600 mm/s時,抗拉強(qiáng)度達(dá)到420 MPa。(5)熱處理可以顯著提高成型件的顯微硬度和拉伸強(qiáng)度。在170℃下,時效2小時之后,成型件的顯微硬度可以增加15~30 HV,抗拉強(qiáng)度可以增加30 MPa左右。
[Abstract]:Selective laser melting (SLM) technology is becoming more and more important as a new material increasing technology. The strength of aluminum alloy melted by selective laser is much higher than that of conventional casting technology. However, the molding properties of SLM AlSi10Mg alloys need to be further studied. In this paper, AlSi10Mg alloy was fabricated by selective laser melting technique. X-ray diffraction (XRD),) metallographic microscope, scanning electron microscope, microhardness tester and tensile tester were used. The effects of SLM process parameters and heat treatment on the microstructure, surface roughness, density and mechanical properties of the molded parts were analyzed. The results show that: (1) the particle size distribution of Al Si10Mg alloy powder is mostly between 5-45 渭 m. The smaller the average particle size is, the better. The particle size below 10 渭 m can easily be blown up by protective gas and suspended in the molding cavity. This part of powder will scatter the laser beam, interfere with the normal output of laser energy, and reduce the service life of the air filter system. Therefore, the use of powder with particle size less than 10 渭 m can be reduced. (2) the microstructure of Al Si10Mg alloy formed by selective laser melting is like a fish scale on the vertical section of laser scanning. A long stripe is observed on a face parallel to the direction of the laser scanning. The microstructure of Si is distributed in the Al matrix as a ring island, and the Al matrix is divided into small islands. (3) when the laser scanning speed is 800-1 000 mm/s and the low power 180 W, the internal cavity defects increase with the increase of the scanning speed. Remelting can increase the density of the molded parts and reduce the hole defects. The density increased by 4.15 and the tensile strength increased by 23.21. (4) with the same heat input, the molding parts with high power and high scanning speed have higher strength than those with low power and low scanning speed. The laser power is 320 W, and the tensile strength reaches 420 MPA at the scanning rate of 1 600 mm/s. (5) the microhardness and tensile strength of the molded parts can be significantly improved by heat treatment. At 170 鈩，

本文編號：2161225