高功率光纖激光熔化成形IN718的工藝及性能Process and Properties of IN718 Formed by High-power Fiber Laser Melting

為研究選擇性激光熔化(selective laser melting,SLM)成形工藝參數對鎳基高溫合金IN718致密度、微觀組織和顯微硬度的影響,借助FORWEDO LM180型SLM成形機采用不同工藝參數制備了分析試樣,通過維氏硬度測試,光學和掃描電鏡觀測以及X射線檢測方法對試樣進行了測試分析。結果表明:隨激光能量密度提高(激光功率起主導作用),成形試樣孔隙缺陷減少,致密度顯著提高;在較大激光能量密度下,合金試樣微觀組織生長趨于均勻,晶粒更加細小;提高激光掃描速率,造成激光輻射和冷卻時間變短,合金微觀組織生長方向變化顯著;SLM工藝復雜的傳熱特點影響試樣組織形貌的復雜程度;合金試樣的顯微硬度隨著組織細化和致密化而提高。

The influence of process parameters forming nickel-based superalloy IN718 by Selective Laser Melting(SLM) on the densification, microstructure and microhardness was studied. Four nickel-based superalloy IN718 samples were fabricated in various processing parameters using FORWEDO LM-180 SLM system. The samples were analyzed with Vickers hardness measurement, SEM and XRD. The results show that the increase of the laser energy density causes the decrease of porosity defects and the significant improvement of their relative density. Under higher laser energy density, microstructures grow more evenly and particles become finer. When the laser scanning speed increases, the laser radiation and cooling time get shorter, so the growing direction of microstructures is changed sharply. Complex heat transfer effects the complexity of the microstructure. Higher extent refinement of grain and densification improve the microhardness.

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