scholarly journals Effect of As-Built and Ground Surfaces on the Fatigue Properties of AlSi10Mg Alloy Produced by Additive Manufacturing

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1432
Author(s):  
Julius Noel Domfang Ngnekou ◽  
Yves Nadot ◽  
Gilbert Henaff ◽  
Julien Nicolai ◽  
Lionel Ridosz
Keyword(s):  
Surface Roughness ◽  
Fatigue Resistance ◽  
Roughness Parameter ◽  
Load Ratio ◽  
Fatigue Tests ◽  
Defect Size ◽  
Fatigue Properties ◽  
Size Analysis ◽  
Powder Bed ◽  
Laser Process

The present work concerns the influence of surface (machined, as-built) on the fatigue resistance of AlSi10Mg produced by a powder-bed laser process. The competition between defects and surface roughness is assessed by using Kitagawa-type diagrams. Samples are printed along three directions: 0°, 45° and 90°. After axial fatigue tests with a load ratio of R = −1, all the fracture surfaces are carefully analysed. The initiation sites can be (i) a defect, (ii) the surface roughness, (iii) the surface ripple. The results indicate that ground surfaces lead to the same fatigue life as as-built surfaces. It is also shown that T6 treatment improves the fatigue resistance. However, when specimen surfaces are as-built or ground, it is difficult to correlate the fatigue results with ‘isolated defect size analysis’ neither roughness parameter for an as-built surface. Therefore, microstructure, residual stresses or multiple initiation should be further analysed to understand the results.

Study on Tensile and High Cycle Fatigue Properties of TiC Particle Reinforced Titanium Matrix Composite

2007 ◽  
Vol 546-549 ◽  
pp. 1535-1540 ◽  
Author(s):  
Li Ying Zeng ◽  
Yong Qing Zhao ◽  
Xiao Nan Mao ◽  
Yun Lian Qi
Keyword(s):  
Matrix Composite ◽  
High Cycle Fatigue ◽  
Load Ratio ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Titanium Matrix ◽  
Titanium Matrix Composite ◽  
Tic Particle ◽  
Hcf Strength

Tensile and high cycle fatigue (HCF) property for TiC particle reinforced titanium matrix composite has been studied in this paper. The results indicated that the composite possessed favorite comprehensive properties. The tensile properties for the composite are superior to that of the common high temperature titanium alloys, e.g. IMI834, Ti-1100. Smooth axial fatigue tests were taken at a frequency of 76Hz with a load ratio R of 0.06 and –1, respectively. And HCF strength for the composite at ambient temperature is 595MPa and 494MPa, respectively.

scholarly journals Position-dependent mechanical characterization of the PBF-EB-manufactured Ti6Al4V alloy

2021 ◽  
Author(s):  
Daniel Kotzem ◽  
Alexandra Höffgen ◽  
Rajevan Raveendran ◽  
Felix Stern ◽  
Kerstin Möhring ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Material Properties ◽  
Mechanical Characterization ◽  
Industrial Applications ◽  
Fatigue Tests ◽  
Ti6al4v Alloy ◽  
Effective Diameter ◽  
Powder Bed Fusion ◽  
Powder Bed

AbstractBy means of additive manufacturing, the production of components with nearly unlimited geometrical design complexity is feasible. Especially, powder bed fusion techniques such as electron beam powder bed fusion (PBF-EB) are currently focused. However, equal material properties are mandatory to be able to transfer this technique to a wide scope of industrial applications. Within the scope of this work, the mechanical properties of the PBF-EB-manufactured Ti6Al4V alloy are investigated as a function of the position on the building platform. It can be stated that as-built surface roughness changes within building platform whereby highest surface roughness detected by computed tomography (Ra = 46.0 ± 5.3 µm) was found for specimens located in the front of the building platform. In contrast, no significant differences in relative density could be determined and specimens can be assumed as nearly fully dense (> 99.9%). Furthermore, all specimens are affected by an undersized effective diameter compared to the CAD data. Fatigue tests revealed that specimens in the front of the building platform show slightly lower performance at higher stress amplitudes as compared to specimens in the back of the building platform. However, process-induced notch-like defects based on the surface roughness were found to be the preferred location for early crack initiation.

An Effect of Surface Laser Hardening on Deformations and Fatigue Properties of 42CrMo4 Steel Specimens

2013 ◽  
Vol 486 ◽  
pp. 54-57
Author(s):  
Ivo Černý ◽  
Jiří Sís
Keyword(s):  
Residual Stresses ◽  
Laser Treatment ◽  
Fatigue Resistance ◽  
Industrial Applications ◽  
Fatigue Tests ◽  
Laser Hardening ◽  
Small Samples ◽  
Fatigue Properties ◽  
Basic Material ◽  
Subsurface Layers

Laser hardening is an advanced method of surface heat treatment with wide possibilities of industrial applications. Considering the fact that this technology is fairly new and is being developed, knowledge about effects on properties of materials treated by this technology are still limited, particularly from the viewpoint of mechanical and particularly fatigue properties. As a dependence of numerous parameters of the treatment, basic material and its state and also size of treated pieces or specimens, not only substantial changes of microstructure in the surface and subsurface layers occur, but also residual stresses and connected deformations. Results of an experimental investigation of effects of laser treatment with selected parameters on deformations and fatigue resistance of relatively small samples of 8 x 8 mm cross section are presented and discussed in this work. Effects of surface speed of the laser beam was evaluated, then effects of fixation of the specimens to rigid supporting steel plate on changes of deflection caused by the laser treatment and eventually, changes of the deformations after releasing the specimens from the supporting plate. Results are in a good agreement with residual stress measurements. Fatigue tests indicated possibilities of favourable effects of laser treatment on fatigue resistance. Results are discussed considering an occurrence of inclusions in the material, residual stresses and fatigue damage mechanisms.

scholarly journals Influence of as-built surface and heat treatment on the fatigue resistance of Additively Layer Manufacturing (ALM) AlSi10Mg alloy.

2018 ◽  
Vol 165 ◽  
pp. 02004 ◽  
Author(s):  
Julius Noel Domfang Ngnekou ◽  
Julien Nicolai ◽  
Yves Nadot ◽  
Gilbert Henaff ◽  
Lionel Ridosz
Keyword(s):  
Heat Treatment ◽  
Fatigue Resistance ◽  
Fatigue Behavior ◽  
Load Ratio ◽  
Defect Size ◽  
Machined Surface ◽  
Layer Manufacturing ◽  
Critical Defect ◽  
Critical Defect Size ◽  
The Impact

This work concerns the fatigue resistance of a AlSi10Mg material produced by additive manufacturing, and more precisely the competition between as built manufacturing surface and as-machined surface on the fatigue resistance. Samples were built by a powder-bed process with an EOS-M280 machine using standard in two configurations (0° and 90°) in order to evaluate the impact of building direction on fatigue life. The impact of as-built surface on fatigue behavior is quantified for each specimen configuration. A T6 heat treatment is performed on samples in order to evaluate the impact of microstructure on fatigue behavior. For each configurations, the S-N curves is determined in as-built and T6 materials with a load ratio R= -1. The fracture surfaces are carefully analyzed in order to determine the critical defect size for each sample. A Kitagawa type diagram representing the fatigue limit as a function of the defect size is derived from these measurements. All the results were compared to those obtained in asmachined samples.

Influence of Charge Composition on the Structure and Fatigue Properties of Nodular Cast Irons

2014 ◽  
Vol 782 ◽  
pp. 295-300
Author(s):  
Alan Vaško ◽  
Libor Trško ◽  
Mária Chalupová
Keyword(s):  
High Frequency ◽  
Load Ratio ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Steel Scrap ◽  
Charge Composition ◽  
Loading Frequency ◽  
Cast Irons ◽  
Metallurgical Silicon ◽  
A Charge

The contribution deals with comparison of microstructure and fatigue properties of synthetic nodular cast irons with a different ratio of steel scrap in a charge. Chemical composition of individual meltages was regulated alternatively by ferrosilicon (FeSi) and carburizer or metallurgical silicon carbide (SiC). The fatigue tests were run at high-frequency sinusoidal cyclic push-pull loading (frequency f 20 kHz, load ratio R = 1, temperature T = 20 ± 5 °C) using the ultrasonic testing equipment KAUP-ZU. The paper shows the influence of charge composition on microstructure, fatigue properties and micromechanisms of failure.

scholarly journals Microstructure and Fatigue Behavior of a Ni-Cu-Sn Alloy

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 888 ◽  
Author(s):  
Leonardo Bertini ◽  
Francesco Bucchi ◽  
Francesco Frendo ◽  
Renzo Valentini
Keyword(s):  
Fatigue Behavior ◽  
Load Ratio ◽  
Tensile Tests ◽  
Strength Properties ◽  
Fatigue Tests ◽  
Raw Material ◽  
Fatigue Properties ◽  
Test Results ◽  
Hardness Tests ◽  
Sem Analyses

In this paper, the static and fatigue properties of a Cu-Ni-Sn alloy are investigated. Tensile tests, hardness tests and microstructural analyses using optical and scanning electron microscopy (SEM) were performed and two sets of fatigue tests, with load ratio (R) R = − 1 and R = 0 , respectively, were carried out. The results showed the capability of the alloy to bear high static stress, thanks to its good strength properties. However, the fatigue tests showed a strong sensitivity of the alloy fatigue properties depending on the raw material batch. The comparison between microstructural analyses and fatigue test results showed a strong correlation; in particular, the specimens having a more inhomogeneous microstructure showed lower durability. In addition, the different microstructure also affected the fracture surface morphology as highlighted by SEM analyses.

scholarly journals On the Relevance of Volumetric Energy Density in the Investigation of Inconel 718 Laser Powder Bed Fusion

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 538 ◽  
Author(s):  
Fabrizia Caiazzo ◽  
Vittorio Alfieri ◽  
Giuseppe Casalino
Keyword(s):  
Surface Roughness ◽  
Energy Density ◽  
Process Parameters ◽  
Vickers Hardness ◽  
Powder Bed Fusion ◽  
Processing Conditions ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Fractional Density ◽  
Experimental Variation

Laser powder bed fusion (LPBF) can fabricate products with tailored mechanical and surface properties. In fact, surface texture, roughness, pore size, the resulting fractional density, and microhardness highly depend on the processing conditions, which are very difficult to deal with. Therefore, this paper aims at investigating the relevance of the volumetric energy density (VED) that is a concise index of some governing factors with a potential operational use. This paper proves the fact that the observed experimental variation in the surface roughness, number and size of pores, the fractional density, and Vickers hardness can be explained in terms of VED that can help the investigator in dealing with several process parameters at once.

scholarly journals Fatigue Properties of AZ31B Magnesium Alloy Processed by Equal-Channel Angular Pressing

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1191
Author(s):  
Ryuichi Yamada ◽  
Shoichiro Yoshihara ◽  
Yasumi Ito
Keyword(s):  
Magnesium Alloy ◽  
Equal Channel Angular Pressing ◽  
Low Cycle Fatigue ◽  
Annealed Sample ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Angular Pressing ◽  
Fundamental Research ◽  
Number Of Cycles ◽  
Biodegradable Magnesium

A stent is employed to expand a narrowed tubular organ, such as a blood vessel. However, the persistent presence of a stainless steel stent yields several problems of late thrombosis, restenosis and chronic inflammation reactions. Biodegradable magnesium stents have been introduced to solve these problems. However, magnesium-based alloys suffer from poor ductility and lower than desired fatigue performance. There is still a huge demand for further research on new alloys and stent designs. Then, as fundamental research for this, AZ31 B magnesium alloy has been investigated for the effect of equal-channel angular pressing on the fatigue properties. ECAP was conducted for one pass and eight passes at 300 °C using a die with a channel angle of 90°. An annealed sample and ECAP sample of AZ31 B magnesium alloy were subjected to tensile and fatigue tests. As a result of the tensile test, strength in the ECAP (one pass) sample was higher than in the annealed sample. As a result of the fatigue test, at stress amplitude σa = 100 MPa, the number of cycles to failure was largest in the annealed sample, medium in the ECAP (one pass) sample and lowest in the ECAP (eight passes) sample. It was suggested that the small low cycle fatigue life of the ECAP (eight passes) sample is attributable to severe plastic deformation.

scholarly journals Corrosion Fatigue Characteristics of 316L Stainless Steel Fabricated by Laser Powder Bed Fusion

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1046
Author(s):  
Balachander Gnanasekaran ◽  
Jie Song ◽  
Vijay Vasudevan ◽  
Yao Fu
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Corrosion Fatigue ◽  
Fatigue Properties ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Corrosion Properties ◽  
Powder Bed ◽  
Fatigue Characteristics

Laser powder bed fusion (LPBF) has been increasingly used in the fabrication of dense metallic structures. However, the corrosion related properties of LPBF alloys, in particular environment-assisted cracking, such as corrosion fatigue properties, are not well understood. In this study, the corrosion and corrosion fatigue characteristics of LPBF 316L stainless steels (SS) in 3.5 wt.% NaCl solution have been investigated using an electrochemical method, high cycle fatigue, and fatigue crack propagation testing. The LPBF 316L SSs demonstrated significantly improved corrosion properties compared to conventionally manufactured 316L, as reflected by the increased pitting and repassivation potentials, as well as retarded crack initiation. However, the printing parameters did not strongly affect the pitting potentials. LPBF samples also demonstrated enhanced capabilities of repassivation during the fatigue crack propagation. The unique microstructural features introduced during the printing process are discussed. The improved corrosion and corrosion fatigue properties are attributed to the presence of columnar/cellular subgrains formed by dislocation networks that serve as high diffusion paths to transport anti-corrosion elements.

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