Fatigue Damage Evolution in SS316L Produced by Powder Bed Fusion in Different Orientations with Reused Powder Feedstock

IF 2 3区工程技术 Q2 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Experimental Mechanics Pub Date : 2024-09-26 DOI:10.1007/s11340-024-01118-1

M. Kopec, U. Gunputh, G. Williams, W. Macek, Z.L. Kowalewski, P. Wood

{"title":"Fatigue Damage Evolution in SS316L Produced by Powder Bed Fusion in Different Orientations with Reused Powder Feedstock","authors":"M. Kopec, U. Gunputh, G. Williams, W. Macek, Z.L. Kowalewski, P. Wood","doi":"10.1007/s11340-024-01118-1","DOIUrl":null,"url":null,"abstract":"<div><h3>Background</h3><p>Metal Laser Powder Bed Fusion Melting (LPBF-M) is considered economically viable and environmentally sustainable because of the possibility of reusing the residual powder feedstock leftover in the build chamber after a part build is completed. There is however limited information on the fatigue damage development of LPBF-M samples made from reused feedstock.</p><h3>Objective</h3><p>In this paper, the stainless steel 316 L (SS316L) powder feedstock was examined and characterised after 25 reuses, following which the fatigue damage development of material samples made from the reused powder was assessed.</p><h3>Methods</h3><p>The suitability of the powder to LPBF-M technology was evaluated by microstructural observations and measurements of Hall flow, apparent and tapped density as well as Carr’s Index and Hausner ratio. LPBF-M bar samples in three build orientations (Z – vertical, XY – horizontal, ZX – 45° from the build plate) were built for fatigue testing. They were then subjected to fatigue testing under load control using full tension and compression cyclic loading and stress asymmetry coefficient equal to -1 in the range of stress amplitude from ± 300 MPa to ± 500 MPa.</p><h3>Results</h3><p>Samples made from reused powder (25 times) in the LPBF-M process exhibited similar fatigue performance to fresh unused powder although a lower ductility for vertical samples was observed during tensile testing. Printing in horizontal (XY) and diagonal (ZX) directions, with reused powder, improved the service life of the SS316L alloy in comparison to the vertical (Z).</p><h3>Conclusions</h3><p>Over the 25 reuses of the powder feedstock there was no measurable difference in the flowability between the fresh (Hall Flow: 21.4 s/50 g) and reused powder (Hall Flow: 20.6 s/50 g). This confirms a uniform and stable powder feeding process during LPBF-M for both fresh and reused powder. The analysis of fatigue damage parameter, D, concluded cyclic plasticity and ratcheting to be the main mechanism of damage.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 4","pages":"427 - 442"},"PeriodicalIF":2.0000,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-024-01118-1.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Experimental Mechanics","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s11340-024-01118-1","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, CHARACTERIZATION & TESTING","Score":null,"Total":0}

引用次数: 0

Abstract

Background

Metal Laser Powder Bed Fusion Melting (LPBF-M) is considered economically viable and environmentally sustainable because of the possibility of reusing the residual powder feedstock leftover in the build chamber after a part build is completed. There is however limited information on the fatigue damage development of LPBF-M samples made from reused feedstock.

Objective

In this paper, the stainless steel 316 L (SS316L) powder feedstock was examined and characterised after 25 reuses, following which the fatigue damage development of material samples made from the reused powder was assessed.

Methods

The suitability of the powder to LPBF-M technology was evaluated by microstructural observations and measurements of Hall flow, apparent and tapped density as well as Carr’s Index and Hausner ratio. LPBF-M bar samples in three build orientations (Z – vertical, XY – horizontal, ZX – 45° from the build plate) were built for fatigue testing. They were then subjected to fatigue testing under load control using full tension and compression cyclic loading and stress asymmetry coefficient equal to -1 in the range of stress amplitude from ± 300 MPa to ± 500 MPa.

Results

Samples made from reused powder (25 times) in the LPBF-M process exhibited similar fatigue performance to fresh unused powder although a lower ductility for vertical samples was observed during tensile testing. Printing in horizontal (XY) and diagonal (ZX) directions, with reused powder, improved the service life of the SS316L alloy in comparison to the vertical (Z).

Conclusions

Over the 25 reuses of the powder feedstock there was no measurable difference in the flowability between the fresh (Hall Flow: 21.4 s/50 g) and reused powder (Hall Flow: 20.6 s/50 g). This confirms a uniform and stable powder feeding process during LPBF-M for both fresh and reused powder. The analysis of fatigue damage parameter, D, concluded cyclic plasticity and ratcheting to be the main mechanism of damage.

查看原文本刊更多论文

粉末床熔炼不同取向SS316L材料的疲劳损伤演化

金属激光粉末床熔炼（LPBF-M）被认为是经济可行和环境可持续的，因为在零件构建完成后，可以再利用构建腔中剩余的残余粉末原料。然而，关于再利用原料制成的LPBF-M样品的疲劳损伤发展的信息有限。目的对不锈钢316l （SS316L）粉末原料进行了25次重复使用后的检测和表征，并对重复使用粉末制成的材料样品的疲劳损伤发展进行了评价。方法通过显微组织观察、霍尔流量、表观密度、密度、卡尔指数、豪斯纳比等测量，评价粉末对LPBF-M工艺的适宜性。LPBF-M棒材样品在三个构建方向（Z -垂直，XY -水平，ZX - 45°与构建板）构建进行疲劳测试。在±300 MPa ~±500 MPa应力幅值范围内，采用全拉、全压缩循环加载，应力不对称系数为-1，进行载荷控制下的疲劳试验。结果：在LPBF-M工艺中，由重复使用的粉末（25次）制成的样品与新鲜未使用的粉末具有相似的疲劳性能，尽管在拉伸测试中观察到垂直样品的延展性较低。在水平（XY）和对角线（ZX）方向上印刷，与垂直(Z)方向相比，使用重复使用的粉末提高了SS316L合金的使用寿命。在25次重复使用的粉末原料中，新鲜粉末（霍尔流量：21.4 s/50 g）和重复使用粉末（霍尔流量：20.6 s/50 g）的流动性没有可测量的差异。这证实了在LPBF-M过程中，新鲜和重复使用的粉末都是均匀稳定的粉末进料过程。通过对疲劳损伤参数D的分析，得出循环塑性和棘轮是损伤的主要机理。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Experimental Mechanics 物理-材料科学：表征与测试

CiteScore

4.40

自引率

16.70%

发文量

111

审稿时长

3 months

期刊介绍： Experimental Mechanics is the official journal of the Society for Experimental Mechanics that publishes papers in all areas of experimentation including its theoretical and computational analysis. The journal covers research in design and implementation of novel or improved experiments to characterize materials, structures and systems. Articles extending the frontiers of experimental mechanics at large and small scales are particularly welcome. Coverage extends from research in solid and fluids mechanics to fields at the intersection of disciplines including physics, chemistry and biology. Development of new devices and technologies for metrology applications in a wide range of industrial sectors (e.g., manufacturing, high-performance materials, aerospace, information technology, medicine, energy and environmental technologies) is also covered.