AlSi10Mg的激光選區熔化成形研究

AlSi10Mg的激光選區熔化成形研究STUDY ON THE SELECTIVE LASER MELTING OF ALSI10MG

Al合金復雜精密零件的需求日益旺盛，激光選區熔化成形技術（Selective Laser Melting，SLM）成形技術有望為其提供一種快速整體制造方法。但是Al合金對激光吸收率低、熱導性能好且易氧化，SLM成形難度大，質量難以控制。本論文對AlSi10Mg鑄造鋁合金的激光選區熔化成形工藝進行了研究，獲得了致密、性能良好的成形，并對其沉積態和熱處理態進行了靜態拉伸性能測試和顯微組織分析。結果表明：對于AlSi10Mg, 其SLM沉積態的常溫拉伸強度遠高于鑄件標準，延伸率與鑄態相當；退火工藝對激光選區熔化成形試樣的組織及性能有著重要的影響，隨著退火溫度的提高，試樣力學性能發生改變，在300 ℃和2 h退火工藝下，原本均勻分布的顆粒狀Si聚集長大為針狀，使得試樣的強度下降，延伸率升高。由沉積態的500 MPa以上下降到378~406 MPa，延伸率由沉積態的3~3.5%增加到6.5~9.0%。

The growing interest for a wide range of usable Al alloy parts with complex shape in industrial field makes selective laser melting (SLM) stand out as a new technology for rapid prototyping manufacturing. However, the laser absorption of Al alloy is very low and its thermal conductivity coefficient is very large as well as it is very easy to be oxidized, resulting in that the process and quality of SLM is very difficult to control. The objective of this paper is to investigate selective laser melted AlSi10Mg. The investigation involved the influence of process parameters on the relative density and the influence of heat-treatment on the microstructure and mechanical properties. High density and performance were achieved. The results show that the tensile strength, yield strength and micro hardness of the SLMed AlSi10Mg is much higher than that of press wrought AlSi10Mg, but the elongation is as almost same as that of the press wrought AlSi10Mg. The heat treatment has significant effect on the mechanical properties and microstructure of SLMed AlSi10Mg parts. The mechanical properties changes with the annealing temperature. Compared with the mechanical properties without annealing process, the tensile strength decreases from 507~518Mpa to 378~406Mpa and the elongation increases from 3~3.5% to 6.5~9.0% when the annealing temperature is 300°C and the soap time is 2h because of the changes in the morphology and distribution of the Si.

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