Residual stresses in LENS® components using neutron diffraction and contour method

Rangaswamy, P.; Griffith, Michelle L.; Prime, Michael B.; Holden, T. M.; Rogge, R. B.; Edwards, John; Sebring, R. J.

doi:10.1016/j.msea.2005.02.019

Cited by 207 publications

(112 citation statements)

References 19 publications

Supporting

Mentioning

102

Contrasting

Order By: Relevance

“…This was applicable to thin wall structures, rectangular structures and square pillars. These compressive stresses were present in the core of the structures while tensile stresses counter balanced them at the outer edges of the samples [11]. However, contrarily to Rangaswamy et al [11], Moat et al [10] additionally found large tensile residual stresses in the transverse direction along the building direction.…”

Section: Residual Stressesmentioning

confidence: 89%

“…The raster direction has shown to have some effect, although not predominant, on the residual stress in the deposit [11], although A.H. Nickel et al showed that the deflection of the substrate was significantly changed depending on raster direction. It was shown that on a beam substrate a lower deflection is expected by choosing a raster direction 90 degrees to the long axis of the substrate.…”

Section: Residual Stressesmentioning

confidence: 99%

“…Laser metal deposition with powder Deposition of material directly on a metal surface using laser is known by many different names such as: laser metal deposition (LMD), direct metal deposition or laser direct metal deposition [6][7][8][9][10], laser engineered net shaping [11], laser consolidation [12], laser rapid manufacturing [13] and more. LMD is a novel method of additive manufacturing which uses a multi-axis CNC machine or robot to guide the laser beam and powder nozzle over the deposition surface.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Review of Laser Deposited Superalloys Using Powder as an Additive

Segerstark¹,

Andersson²,

Svensson³

2014

8th International Symposium on Superalloy 718 and Derivatives (2014)

View full text Add to dashboard Cite

In this paper laser metal deposition (LMD) with blown powder was reviewed with respect to the material behavior of nickel and nickel-iron based superalloys. The key benefits of LMD are claimed to be increased design freedom of components as well as reduced environmental impact since it enables near net shape manufacturing. This review considers the LMD processing parameters such as laser power, powder feed rate, spot size, standoff distance, and traverse speed, together with aspects related to the powder e.g. morphology, porosity, inclusion and satellite content. Special emphasis was put on how these parameters affect the deposit and substrate in terms of cracking, porosity, inclusions, phase transformations, and other material related phenomena. A characteristic microstructure of LMD deposited superalloys has a columnar dendrite growth in the vertical build up direction. The grain growth can however be manipulated, making it more equiaxed by, for instance, altering process parameters and/or scanning path. Residual stresses in LMD samples are unevenly distributed and large residual tensile stresses can be found at the surface of the deposit while large compressive stresses are located close to the substrate in the core of the deposit. One of the most important parameter is considered to be the specific energy input which largely influences the m elt pool during deposition which in turn can be related to the microstructure, residual stress and, process related defects such as porosity, cracking, lack of fusion and, dilution.

show abstract

Section: Residual Stressesmentioning

confidence: 89%

Section: Residual Stressesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Review of Laser Deposited Superalloys Using Powder as an Additive

Segerstark¹,

Andersson²,

Svensson³

2014

8th International Symposium on Superalloy 718 and Derivatives (2014)

View full text Add to dashboard Cite

show abstract

“…The placement of the gage volumes is similar to that of a previous study of residual stress in LENS samples conducted by Rangaswamy et al, [2] which was intended to show how stress varies as a function of position within the coordinate system of the part. However, the plates used in this study are 2 to 4 mm thinner than those measured by Rangaswamy et al, allowing for only one gage volume to be placed in the X direction, as shown in Figure 2.…”

Section: Methodsmentioning

confidence: 99%

“…[1,2] The results of these studies revealed high levels of type I macroscopic residual stress induced within the parts by the net shaping process. However, little is yet known of how the LENS input parameters affect the resulting levels and distributions of internal stresses.…”

Section: Introductionmentioning

confidence: 94%

Residual Stress Measurement of Laser-Engineered Net Shaping AISI 410 Thin Plates Using Neutron Diffraction

Pratt

Felicelli

Wang

et al. 2008

Metall Mater Trans A

View full text Add to dashboard Cite

In an attempt to relate the laser-engineered net shaping (LENS) process parameters, laser power and laser travel speed, to the quality of LENS-produced parts, strain measurements were taken at several predetermined points within seven LENS AISI 410 thin plates using the neutron diffraction method. The residual stresses at these points were then calculated using the measured strain values to ascertain how the internal stress varies as a function of the input parameters and location. It is found that the component of the stress in the vertical direction (i.e., perpendicular to the raster direction of the laser/powder nozzle) is dominant, in agreement with previous reports, and relatively insensitive to variations in process parameters. This was confirmed with numerical simulations performed with a thermomechanical model developed using the commercial program SYSWELD. The simulations also showed a good qualitative agreement with the measured simulated stresses.

show abstract

The Contour Method

Prime

DeWald

2013

Practical Residual Stress Measurement Methods

112

View full text Add to dashboard Cite

The contour method, which is based upon solid mechanics, determines residual stress through an experiment that involves carefully cutting a specimen into two pieces and measuring the resulting deformation due to residual stress redistribution. The measured displacement data are used to compute residual stresses through an analysis that involves a finite element model of the specimen. As part of the analysis, the measured deformation is imposed as a set of displacement boundary conditions on the model. The finite element model accounts for the stiffness of the material and part geometry to provide a unique result. The output is a two-dimensional map of residual stress normal to the measurement plane. The contour method is particularly useful for complex, spatially varying residual stress fields that are difficult (or slow) to map using conventional point wise measurement techniques. For example, the complex spatial variations of residual stress typical of welds are well-characterized using the contour method.Contour method measurements are typically performed on metallic parts, which can be cut using a wire electric discharge machine (EDM). There are no specific size restrictions, but the measurement signal (displacement) scales with specimen size and performing measurements on parts smaller than 5 mm by 5 mm in cross-section requires extreme precision. There are no restrictions on the shape of the specimen due to the fact that complex geometry is accounted for using a finite element model of the part.The contour method is the youngest method covered in this book, having been first presented at a conference in 2000 [1] and then in a journal in 2001 [2]. Therefore, consensus Practical Residual Stress Measurement Methods, First Edition. Edited by Gary S. Schajer.

show abstract

Residual stresses in LENS® components using neutron diffraction and contour method

Cited by 207 publications

References 19 publications

Review of Laser Deposited Superalloys Using Powder as an Additive

Review of Laser Deposited Superalloys Using Powder as an Additive

Residual Stress Measurement of Laser-Engineered Net Shaping AISI 410 Thin Plates Using Neutron Diffraction

The Contour Method

Contact Info

Product

Resources

About