The product manufactured by selective laser sintering (SLS), usually applied in high value engineering products including an airplane, medical support and so on, and needs a careful assessment and analysis of the defects. Defects induced during the 3D printing metals by SLS process are difficult to be predicted and eliminated. The aim of this study is to observe and obtain the statistics of defects so as to utilize the numerical predictions to quantify the variation in the mechanical properties by considering statistical nature of the defects. Specifically one cellular structure is fabricated several times as variation of building directions in two different ways. After manufacturing, the Computed Tomography (CT) technology is used to observe the microstructure in order to evaluate the performance of printed structure. In the raw material of managing steel, the geometrical defects are characterized and categorized into three main groups, i.e. notch, kink and hole. It is found that the directions of above defects are put along with the direction of printing. By reconstruction of CT images, the 3D model of printed structure is built and the parametrization of those geometrical defects and statistics are done. It is also found that when the printing angle is set at 45°, the kink is of most probable to be formed while the notch is likely to be formed at 0°. Based on those statistics data, microstructures including defects are built with random parameters. The macroscopic properties are analyzed to obtain the variation from mean value in macroscopic stiffness, permeability and micro stress. Variation turned out to be huge of micro stress but small in macro stiffness. The numerical result is validated via compression test of macroscopic stiffness for printed specimens. This study can contribute to validation of numerical models and obtained statistics is also applicable in other 3D printed structure.
WEN Pin
,
YE Hongling
,
YANG Qingsheng
. Microstructure Defects and Properties Analysis of Maraging Steel Porous Frame by Selective Laser Sintering[J]. Journal of Mechanical Engineering, 2018
, 54(17)
: 173
-180
.
DOI: 10.3901/JME.2018.17.173
[1] 魏青松,唐萍,吴甲民,等. 激光选区烧结多孔堇青石陶瓷微观结构及性能[J]. 华中科技大学学报,2016(6):46-51. WEI Qingsong,TANG Ping,WU Jiamin,et al. Microstructure and mechanical performance of porous cordierite ceramic parts manufactured by selective laser sintering[J]. Journal of Huazhong University of Science and Technology,2016(6):46-51.
[2] 梁晓康,董鹏,陈济轮,等. 激光选区熔化成形Ti_6Al_4V钛合金的显微组织及性能[J]. 应用激光,2014,34(2):101-104. LIANG Xiaokang,DONG Peng,CHEN Jilun,et al. Microstructure and mechanical properties of selective laser melting Ti-6Al-4V alloy[J]. Applied Laser,2014,34(2):101-104.
[3] CUNNINGHAM R,NARRA S,OZTURK T,et al. Evaluating the effect of processing parameters on porosity in electron beam melted Ti-6Al-4V via synchrotron X-ray microtomography[J]. Journal of The Minerals,Metals and Materials,2016,68:765-771.
[4] ATTAR H,NISCH M,CALIN M,et al. Selective laser melting of in situ titanium-titanium boride composites:Processing, microstructure and mechanical properties[J]. Acta Materialia,2014,76:13-22.
[5] GU D, HE B. Finite element simulation and experimental investigation of residual stresses in selective laser melted Ti-Ni shape memory alloy[J]. Comp Material Science,2016,117:221-232.
[6] GORGULUARSLAN R, CHOI S, SALDANA C. Uncertainty quantification and validation of 3D lattice scaffolds for computer-aided biomedical applications[J]. Journal of Mechanical Behavior of Biomedical Materials,2017,71:428-440.
[7] PIMENTA R,DINIZ S,QUEIROZ G,et al. Reliability-based design recommendations for composite corrugated-web beams[J]. Probabilistic Engineering Mechanics,2012,28:185-193.
[8] LUO Y, LI A, KANG Z. Reliability-based design optimization of adhesive bonded steel-concrete composite beams with probabilistic and non-probabilistic uncertainties[J]. Engineering Structure,2011,33(7):2110-2119.
[9] 毛伟, 连芩,李涤尘,等. 立体空心血管网水凝胶支架的3D打印工艺研究[J]. 机械工程学报,2017,53(9):180-186. MAO Wei,LIAN Qin,LI Dichen,et al. 3D printing process for hydro gel with the three-dimensional micro tubes to mimic vascular network[J]. Chinese Journal of Mechanical Engineering,2017,53(9):180-186.
[10] 万谦,赵海东,邹纯. 铝合金压铸件微观孔洞三维特征及分布的研究[J]. 金属学报,2013,49(3):284-290. WAN Qian,ZHAO Haidong,ZOU Chun. Three-dimensional characterization and distribution of micropores in aluminum alloy high pressures die castings[J]. Acta Metallurgica Sinica,2013,49(3):284-290.
[11] CONCEICAO C,ANTONIO L,HOFFBAUER. Reliability-based design optimization and uncertainty quantification for optimal conditions of composite structures with non-linear behavior[J]. Engineering Structure,2017,153:479-490.
[12] 康建峰,王玲,孙畅宁,等. 面向3d打印可变模量金属假体的微结构设计[J]. 机械工程学报, 2017,53(5):175-180. KANG Jianfeng,WANG Ling,SUN Changning,et al. Microstructure design for 3D printed metal prosthesis of adjustable modulus[J]. Journal of Mechanical Engineering,2017,53(5):175-180.
[13] ZHANG B,LI Y,BAI Q. Defect formation mechanisms in selective laser melting:A review[J]. Chinese Journal of Mechanical Engineering,2017, 30(3):515-527.
[14] MIYAUCHI Y, TAKANO N, WEN P. Stochastic homogenization analysis of FIB-SEM image-based hierarchical model of sprayed porous ZrO2[J]. Mechanical Engineering Letters,2015,1:1-8.
[15] WEN P,TAKANO N,KURITA D. Probabilistic multiscale analysis of three-phase composite material considering uncertainties in both physical and geometrical parameters at microscale[J]. Acta Mechanica,2016,227:2735-2747.
[16] TAKANO N,TAKIZAWA H,WEN P,et al. Stochastic prediction of apparent compressive stiffness of selective laser sintered lattice structure with geometrical imperfection and uncertainty in material property[J]. International Journal of Mechanical Science,2017,134:347-356.
