摘要
激光增材制造铝合金构件室温及高温力学性能对于提升其在航空航天等领域的服役稳定性至关重要。本文研究了成形方式对激光粉末床熔融(LPBF)AlSi10Mg构件室温压缩性能、高温拉伸性能、高周疲劳性能和室温裂纹扩展速率等力学性能的影响规律。结果表明:水平方式成形试样(拉伸、压缩、疲劳等载荷平行于试样铺粉方向)具有更优的压缩性能,表现出更优异的抗压强度及屈服强度(分别为201.0 MPa与251.3 MPa);在高温拉伸试验中,不同成形方向试样的抗拉强度及屈服强度随着试验温度升高(从100℃升至175℃)均呈下降趋势,而延伸率均逐渐升高,且水平方式成形试样的拉伸性能均优于垂直方式成形试样(载荷垂直于试样铺粉方向)。垂直方式成形AlSi10Mg合金试样经历10^(7)循环周次的中值疲劳强度为151.25MPa,疲劳寿命约为2.1×10^(5)周次,疲劳裂纹扩展门槛值为0.981MPa·m^(1/2)。
Objective Owing to their light weight,high specific strength,and excellent corrosion resistance,aluminum alloys are widely used in aerospace,national defense,and other fields.Recently,the demand for high-performance aluminum alloys in various fields is urgent.However,the performance and complexity of aluminum alloy components are limited because of conventional fabrication methods such as casting and forging.Laser additive manufacturing(LAM)has garnered considerable popularity in recent years owing to its high material utilization,short forming cycle,and near-net-shape fabrication.Previous studies have indicated that research on LAM-processed aluminum alloys mostly focus on static mechanical properties(e.g.,tensile properties,compressive properties,friction and wear).Dynamic mechanical properties(e.g.,high cycle fatigue and fatigue crack growth)can be employed to systematically evaluate defects in components and the heterogeneity of the microstructure.Therefore,studying and improving the dynamic mechanical properties of LAM-processed aluminum alloys are crucial.In this study,the effects of different building directions on the mechanical properties(such as room temperature compression and high temperature tension)of LAM-processed aluminum alloy samples are reported,the fatigue property of aluminum alloy components processed by LAM is studied,and the fatigue crack propagation mechanism of the samples is revealed.We hope that the integrated and accurate manufacturing of material-structure-performance can be realized,and an academic reference for the application of LAM-processed aluminum alloys in aerospace and other fields can be provided.Methods Herein,AlSi10Mg powder was used as the starting material.First,standard compression,tensile,fatigue,and fatigue crack-propagation compact tension(CT)specimens were fabricated using laser powder bed fusion(LPBF)along different building directions.Then,the microstructure of the samples was characterized using an optical microscope(OM).The compressive and tensile properties of the samples at room temperature and a high temperature,respectively,under different building directions and the fatigue properties and fatigue crack growth rate of vertical samples(i.e.,the tensile,compressive,and fatigue loads are vertical to the powder spreading direction)were evaluated.Moreover,the effects of LPBF parameters on the aforementioned mechanical properties of the AlSi10Mg alloy were systematically evaluated.Results and Discussions The horizontal samples(i.e.,the tensile,compressive,and fatigue loads are parallel to the powder spreading direction)showed excellent compressive strength and yield strength,reaching 201.0 and 251.3 MPa,respectively(Fig.4).With increasing testing temperature(100--175℃),the tensile and yield strengths of the samples fabricated along different building directions showed a decreasing trend,while the elongation gradually increased.The horizontal samples achieved better tensile and yield strengths than the vertical samples,showing tensile and yield strengths of 195.0and 160.0 MPa at 175℃[Fig.6(d)].The 10~7-cycle median fatigue strength,fatigue life,and threshold of fatigue crack growth of the vertical samples were 151.25 MPa(Fig.7),~2.1×10~5 cycles[Fig.8(a)],and 0.981 MPa·m^(1/2)(Table 1),respectively.Conclusions Herein,AlSi10Mg alloy samples were successfully fabricated along different building directions using LPBF.After static mechanical tests,the room-temperature compressive strength could reach 201.0 MPa and the yield strength was 251.3 MPa.The tensile and yield strengths at 175℃could reach 195.0 and 160.0 MPa,respectively.The static mechanical tests of the samples along different building directions revealed that the horizontal samples showed with better compression properties at room temperature and better tensile properties at a high temperature than the vertical samples.The LPBF-processed AlSi10Mg vertical sample showed excellent 10^(7)-cycle median fatigue strength of 151.25 MPa,while relevant research shows that the high cycle fatigue strength of AlSi12alloys processed using LAM is 88.7 MPa.The excellent high-cycle fatigue resistance of AlSi10Mg processed using LAM was attributed to its unique fine cellular grains and fine Al-Si eutectic phases at grain boundaries.The fatigue life and threshold of fatigue crack growth of the LPBF-processed AlSi10Mg alloy were~2.1×10^(5 )cycles and 0.981 MPa·m^(1/2),respectively.The findings of this study show that the excellent mechanical properties of AlSi10Mg alloys can be obtained by LPBF processing.This study can provide an academic reference for the application of LAM-processed aluminum alloys in aerospace and other fields.
作者
齐世文
荣鹏
黄丹
陈勇
王锐
戴冬华
顾冬冬
Qi Shiwen;Rong Peng;Huang Dan;Chen Yong;Wang Rui;Dai Donghua;Gu Dongdong(Chengdu Aircraft Industrial(Group)Co.,Ltd.,Chengdu 610073,Sichuan,China;College of Materials Science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,Jiangsu,China;Jiangsu Provincial Engineering Laboratory for Laser Additive Manufacturing of High-Performance Metallic Components,Nanjing 210016,Jiangsu,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2022年第8期1-11,共11页
Chinese Journal of Lasers
基金
装备预先研究领域基金项目-快速扶持项目(JZX7Y20210263400301)。
关键词
激光技术
激光增材制造
激光粉末床熔融
高温力学性能
疲劳强度
疲劳裂纹扩展速率
laser technique
laser additive manufacturing
laser powder bed fusion
high temperature mechanical properties
fatigue strength
fatigue crack growth rate
作者简介
通信作者:顾冬冬,dongdonggu@nuaa.edu.cn。
