Characterisation of Nickel-Based Superalloys Manufactued by Electron Beam Melting

Nickel-based superalloys have been manufactured by electron beam melting (EBM). EBM is an additive manufacturing process for direct production of metal parts. The part is build up by successive melting of metal powder layers in a vacuum chamber using electron beam. In this study, the microstructure, texture and the physical properties of nickel-based superalloys manufactured by EBM were thoroughly characterised by different methods, e.g. XRD, DTA, SEM, EDS, EBSD, TEM and APFIM. The investigated alloys were Inconel alloy 600, Udimet alloy 720 and Inconel alloy 718; they are strengthened by different hardening mechanisms. The EBM materials were highly textured and oriented with the directions in the building direction and in the scanning directions of the electron beam. Furthermore, the grains are elongated in the building direction and are up to several millimetres in length. The mechanical properties of heat treated Inconel alloy 718 manufactured by EBM are to large extent comparable with conventional material. Additionally, the same alloys were manufactured by casting and directional solidification, in order to compare the solidification and precipitation behaviour with the EBM samples. The solidification rate was fastest in the EBM process and slowest in directional solidification. Macrosegregation did not occur in the EBM samples, but in the cast and directionally solidified samples.Enhanced understanding about rapid solidification and local melting has been gained during this study. This should be of value also for similar processes, e.g. additive manufacturing and welding. EBM is a promising technology for direct manufacturing of highly textured nickel-based superalloy parts. A suitable application would be parts currently manufactured by directional solidification. Using EBM, both cost and time can be reduced as no mould is required. Furthermore, it would be possible to tailor both the geometry and the texture of each single part in the EBM process

Characterisation of Nickel-Based Superalloys Manufactued by Electron Beam Melting

Nickel-based superalloys have been manufactured by electron beam melting (EBM). EBM is an additive manufacturing process for direct production of metal parts. The part is build up by successive melting of metal powder layers in a vacuum chamber using electron beam. In this study, the microstructure, texture and the physical properties of nickel-based superalloys manufactured by EBM were thoroughly characterised by different methods, e.g. XRD, DTA, SEM, EDS, EBSD, TEM and APFIM. The investigated alloys were Inconel alloy 600, Udimet alloy 720 and Inconel alloy 718; they are strengthened by different hardening mechanisms. The EBM materials were highly textured and oriented with the directions in the building direction and in the scanning directions of the electron beam. Furthermore, the grains are elongated in the building direction and are up to several millimetres in length. The mechanical properties of heat treated Inconel alloy 718 manufactured by EBM are to large extent comparable with conventional material. Additionally, the same alloys were manufactured by casting and directional solidification, in order to compare the solidification and precipitation behaviour with the EBM samples. The solidification rate was fastest in the EBM process and slowest in directional solidification. Macrosegregation did not occur in the EBM samples, but in the cast and directionally solidified samples.Enhanced understanding about rapid solidification and local melting has been gained during this study. This should be of value also for similar processes, e.g. additive manufacturing and welding. EBM is a promising technology for direct manufacturing of highly textured nickel-based superalloy parts. A suitable application would be parts currently manufactured by directional solidification. Using EBM, both cost and time can be reduced as no mould is required. Furthermore, it would be possible to tailor both the geometry and the texture of each single part in the EBM process

Nondestructive Evaluation with Laser Ultrasound of Powder Bed Fusion Printed Metal

Many of the main advantages of 3D printing metal components, for example the possibility to manufacture parts of high geometric complexity in small series, typically make the nondestructive quality control difficult and resource intense. A number of published studies have proposed in-process nondestructive evaluation of the printed material, as it is built layer by layer, as a possible general approach solution to this difficulty. Previous studies have also indicated that the non-contact nondestructive testing method laser ultrasound might be an applicable method to conduct such an in-process nondestructive evaluation of 3D printed parts. Potential pros of such an ultrasonic based evaluation, as compared to more process monitoring like approaches (e.g. acoustic emission from the printing process) would for example be increased defect characterization capabilities.In this work laser ultrasonic nondestructive evaluation of both electron beam and laser beam powder bed fusion printed metal is demonstrated. Nickel-base and Stainless Steel samples are evaluated both from a machined surface and, in order to simulate the in-process setup, from the as-printed top surface.The laser ultrasonic evaluation results are then compared to results from other material characterization methods, such as light optical microscopy and X-ray inspection. Designed artificial defects as well as process material anomalies could be detected with the proposed laser ultrasonic evaluation. In some cases material defects could be detected also when the laser ultrasonic evaluation was performed from the as-printed top surface.Our results are similar to other studies that have been reported on the subject: laser ultrasound can be utilized to detect material anomalies of interest in powder bed fusion printed metal material. Further research is required in order to better understand and improve the capability and reliability of the nondestructive evaluation method.QC 20191001</p

Nondestructive Evaluation with Laser Ultrasound of Powder Bed Fusion Printed Metal Parts

Introduction/Purpose Many of the main advantages of 3D printing metal components, for example the possibility to manufacture components of high geometriccomplexity in small series, typically make the nondestructive quality control difficult and resource intense. A number of published studies haveproposed in-process quality control of the component, as it is built layer by layer, as a possible general approach solution to this difficulty. Previousstudies have also indicated that the non-contact nondestructive testing method laser ultrasound might be an applicable method to conduct such anin-process nondestructive evaluation of 3D printed components. Methods In this work laser ultrasonic nondestructive evaluation of both electron beam and laser beam powder bed fusion printed metal parts isdemonstrated. Nickel-base and Stainless Steel samples are evaluated both from a machined surface and, in order to simulate the in-process setup,from the as-printed top surface. Results The laser ultrasonic evaluation results are compared to results from other material characterization methods. Designed artificial defects as well asprocess material anomalies could be detected with the proposed laser ultrasonic evaluation, both when the evaluation was performed from the asprintedtop surface as well as from the machined surface. Conclusions We conclude that laser ultrasound can be utilized to detect material anomalies of interest in powder bed fusion printed metal parts. Furtherresearch is required in order to better understand and improve the capability and reliability of the nondestructive evaluation method.QC 20190930</p

Nondestructive Evaluation with Laser Ultrasound of Powder Bed Fusion Printed Metal

Many of the main advantages of 3D printing metal components, for example the possibility to manufacture parts of high geometric complexity in small series, typically make the nondestructive quality control difficult and resource intense. A number of published studies have proposed in-process nondestructive evaluation of the printed material, as it is built layer by layer, as a possible general approach solution to this difficulty. Previous studies have also indicated that the non-contact nondestructive testing method laser ultrasound might be an applicable method to conduct such an in-process nondestructive evaluation of 3D printed parts. Potential pros of such an ultrasonic based evaluation, as compared to more process monitoring like approaches (e.g. acoustic emission from the printing process) would for example be increased defect characterization capabilities.In this work laser ultrasonic nondestructive evaluation of both electron beam and laser beam powder bed fusion printed metal is demonstrated. Nickel-base and Stainless Steel samples are evaluated both from a machined surface and, in order to simulate the in-process setup, from the as-printed top surface.The laser ultrasonic evaluation results are then compared to results from other material characterization methods, such as light optical microscopy and X-ray inspection. Designed artificial defects as well as process material anomalies could be detected with the proposed laser ultrasonic evaluation. In some cases material defects could be detected also when the laser ultrasonic evaluation was performed from the as-printed top surface.Our results are similar to other studies that have been reported on the subject: laser ultrasound can be utilized to detect material anomalies of interest in powder bed fusion printed metal material. Further research is required in order to better understand and improve the capability and reliability of the nondestructive evaluation method.QC 20191001</p

Nondestructive Evaluation with Laser Ultrasound of Powder Bed Fusion Printed Metal

Many of the main advantages of 3D printing metal components, for example the possibility to manufacture parts of high geometric complexity in small series, typically make the nondestructive quality control difficult and resource intense. A number of published studies have proposed in-process nondestructive evaluation of the printed material, as it is built layer by layer, as a possible general approach solution to this difficulty. Previous studies have also indicated that the non-contact nondestructive testing method laser ultrasound might be an applicable method to conduct such an in-process nondestructive evaluation of 3D printed parts. Potential pros of such an ultrasonic based evaluation, as compared to more process monitoring like approaches (e.g. acoustic emission from the printing process) would for example be increased defect characterization capabilities.In this work laser ultrasonic nondestructive evaluation of both electron beam and laser beam powder bed fusion printed metal is demonstrated. Nickel-base and Stainless Steel samples are evaluated both from a machined surface and, in order to simulate the in-process setup, from the as-printed top surface.The laser ultrasonic evaluation results are then compared to results from other material characterization methods, such as light optical microscopy and X-ray inspection. Designed artificial defects as well as process material anomalies could be detected with the proposed laser ultrasonic evaluation. In some cases material defects could be detected also when the laser ultrasonic evaluation was performed from the as-printed top surface.Our results are similar to other studies that have been reported on the subject: laser ultrasound can be utilized to detect material anomalies of interest in powder bed fusion printed metal material. Further research is required in order to better understand and improve the capability and reliability of the nondestructive evaluation method.QC 20191001</p

Nondestructive Evaluation with Laser Ultrasound of Powder Bed Fusion Printed Metal Parts

Introduction/Purpose Many of the main advantages of 3D printing metal components, for example the possibility to manufacture components of high geometriccomplexity in small series, typically make the nondestructive quality control difficult and resource intense. A number of published studies haveproposed in-process quality control of the component, as it is built layer by layer, as a possible general approach solution to this difficulty. Previousstudies have also indicated that the non-contact nondestructive testing method laser ultrasound might be an applicable method to conduct such anin-process nondestructive evaluation of 3D printed components. Methods In this work laser ultrasonic nondestructive evaluation of both electron beam and laser beam powder bed fusion printed metal parts isdemonstrated. Nickel-base and Stainless Steel samples are evaluated both from a machined surface and, in order to simulate the in-process setup,from the as-printed top surface. Results The laser ultrasonic evaluation results are compared to results from other material characterization methods. Designed artificial defects as well asprocess material anomalies could be detected with the proposed laser ultrasonic evaluation, both when the evaluation was performed from the asprintedtop surface as well as from the machined surface. Conclusions We conclude that laser ultrasound can be utilized to detect material anomalies of interest in powder bed fusion printed metal parts. Furtherresearch is required in order to better understand and improve the capability and reliability of the nondestructive evaluation method.QC 20190930</p

Nondestructive Evaluation with Laser Ultrasound of Powder Bed Fusion Printed Metal Parts

Introduction/Purpose Many of the main advantages of 3D printing metal components, for example the possibility to manufacture components of high geometriccomplexity in small series, typically make the nondestructive quality control difficult and resource intense. A number of published studies haveproposed in-process quality control of the component, as it is built layer by layer, as a possible general approach solution to this difficulty. Previousstudies have also indicated that the non-contact nondestructive testing method laser ultrasound might be an applicable method to conduct such anin-process nondestructive evaluation of 3D printed components. Methods In this work laser ultrasonic nondestructive evaluation of both electron beam and laser beam powder bed fusion printed metal parts isdemonstrated. Nickel-base and Stainless Steel samples are evaluated both from a machined surface and, in order to simulate the in-process setup,from the as-printed top surface. Results The laser ultrasonic evaluation results are compared to results from other material characterization methods. Designed artificial defects as well asprocess material anomalies could be detected with the proposed laser ultrasonic evaluation, both when the evaluation was performed from the asprintedtop surface as well as from the machined surface. Conclusions We conclude that laser ultrasound can be utilized to detect material anomalies of interest in powder bed fusion printed metal parts. Furtherresearch is required in order to better understand and improve the capability and reliability of the nondestructive evaluation method.QC 20190930</p

Role of Superficial Defects and Machining Depthin Tensile Properties of Electron Beam Melting (EBM)Made Inconel 718

Since there is no report on the influence of machining depth on electron beam melting (EBM) parts, this paper investigated the role of superficial defects and machining depth in the performance of EBM made Inconel 718 (IN718) samples. Therefore, as-built EBM samples were analyzed against the shallow-machined (i.e., only removal of outer surfaces) and deep-machined (i.e., deep surface removal into the material) parts. It was shown that both as-built and shallow-machined samples had a drastically lower yield strength (970 ± 50 MPa), ultimate tensile stress (1200 ± 40 MPa), and ductility (28 ± 2%) compared to the deep-machined samples. This was since premature failure occurred due to various superficial defects. The superficial defects appeared in two levels, as (1) notches and pores on the surface and (2) irregular pores and cracks within the subsurface. Since the latter occurred down to 2 mm underneath the surface, shallow machining only exposed the subsurface defects to outer surfaces. Thus, the shallow-machined parts achieved only 68% and 8% of UTS and elongation of the deep-machined parts, respectively. This low performance occurred to be comparable to the as-built parts, which failed prematurely due to the high fraction surface voids and notches as well as the subsurface defects.QC 20210824</p