| 引用本文: | 韩静,吕俊霞,王晋,李菲祺,张跃飞,成志忠.选区激光熔化AlSi10Mg合金不同温度原位拉伸变形行为及断裂机理研究[J].材料科学与工艺,2022,30(6):10-19.DOI:10.11951/j.issn.1005-0299.20220070. |
| HAN Jing,LÜ Junxia,WANG Jin,LI Feiqi,ZHANG Yuefei,CHENG Zhizhong.In-situ investigation of deformation behavior and fracture mechanism of selective laser melting AlSi10Mg alloy at different temperatures[J].Materials Science and Technology,2022,30(6):10-19.DOI:10.11951/j.issn.1005-0299.20220070. |
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| 选区激光熔化AlSi10Mg合金不同温度原位拉伸变形行为及断裂机理研究 |
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韩静1,吕俊霞1,王晋2,李菲祺1,张跃飞2,成志忠3
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(1.北京工业大学 材料与制造学部,北京 100124;2.浙江大学 材料科学与工程学院,杭州 310027; 3.北京空间飞行器总体设计部,北京 100094)
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| 摘要: |
| 为了提高选区激光熔化AlSi10Mg合金在航空航天领域的应用,基于自主研发的原位SEM高温拉伸台,本文对比分析了原位拉伸非校准样品的选区激光熔化AlSi10Mg合金在室温、200、300 ℃条件下的力学性能与显微组织动态演化,并总结了断裂机理。结果表明,选区激光熔化AlSi10Mg合金的显微结构由α-Al基体、共晶Si和大量的气孔组成,且共晶Si呈连续网格状均匀分布在α-Al基体上。随着温度的升高,选区激光熔化AlSi10Mg合金的强度降低。屈服强度从室温的207 MPa降低到300 ℃时的52 MPa,极限抗拉强度从室温的304 MPa降低到300 ℃时的71 MPa,延伸率则随温度的升高而增大,从室温的7.4%增大到300 ℃时的59.5%。室温拉伸过程中试样并未出现明显的颈缩现象,而是随着温度的升高,试样的颈缩现象逐渐明显,表明试样经历了更加充分的塑性变形, 并且随着温度的升高,试样的断裂位置越来越偏离标距段中心。通过对试样变形行为的研究发现,200 ℃时,变形主要集中在晶内,发生晶内滑移；而300 ℃时滑移主要集中在晶界,导致晶界滑移。由于试样表面及内部存在大量缺陷,因此,室温下选区激光熔化AlSi10Mg合金的断裂机理为熔池边界的组织突变结合孔洞连通造成的准解理断裂。随着温度的升高,由于初始孔洞边缘的应力集中产生新的孔洞形核,新形核的孔洞与相邻孔洞相连通,导致试样的最终断裂。 |
| 关键词: 选区激光熔化 AlSi10Mg合金 原位拉伸 力学性能 断裂机理 |
| DOI：10.11951/j.issn.1005-0299.20220070 |
| 分类号:TG146.21 |
| 文献标识码:A |
| 基金项目:北京市自然科学基金重点项目(KZ202110005006). |
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| In-situ investigation of deformation behavior and fracture mechanism of selective laser melting AlSi10Mg alloy at different temperatures |
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HAN Jing1,Lü Junxia1,WANG Jin2,LI Feiqi1,ZHANG Yuefei2,CHENG Zhizhong3
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(1.Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China; 2.School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China; 3.Beijing Institute of Spacecraft System Engineering, Beijing 100094, China)
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| Abstract: |
| For the further application of selective laser melting (SLM) AlSi10Mg alloy in aerospace, the microstructure and mechanical properties of SLM AlSi10Mg alloy at room temperature, 200 ℃, and 300 ℃ were analyzed based on the self-developed in-situ SEM high-temperature tensile test stage, and the fracture mechanism was summarized. Results show that the microstructure of SLM AlSi10Mg alloy was composed of α-Al matrix, eutectic Si, and plenty of pores, and eutectic Si distributed uniformly in the α-Al matrix with a continuous network structure. With temperature increasing, the yield strength and ultimate tensile strength of SLM AlSi10Mg alloy decreased from 207 MPa and 304 MPa at room temperature to 52 MPa and 71 MPa at 300 ℃, whereas the elongation increased from 7.4% at room temperature to 59.5% at 300 ℃. No evident necking behavior of specimen was observed at room temperature during the tensile test. As the temperature increased, the necking behavior became obvious, which suggests that the specimen experienced more sufficient plastic deformation. Moreover, the fracture position of the specimen more and more deviated from the center of the marking section with increasing temperature. By analyzing the deformation behavior of specimen, it was found that at 200 ℃ intracrystalline deformation was dominant and intracrystalline slip occurred, while at 300 ℃ the slip was mainly at grain boundary, which resulted in grain boundary slip. Since there were a large number of defects inside and on the surface of the specimen, the fracture mechanism of SLM AlSi10Mg alloy was the quasi-cleavage fracture caused by the microstructure change at the molten pool boundary combined with the connection of pores. With the increase in temperature, due to the stress concentration at the edge of the initial pores, new void nucleation was generated, and the new void nucleation was connected with adjacent pores, leading to the final fracture of the specimen. |
| Key words: selective laser melting AlSi10Mg alloy in-situ tension mechanical properties fracture mechanism |
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