Effect of processing parameters of electron beam melting machine on properties of Ti-6Al-4V parts

2016 ◽  
Vol 22 (3) ◽  
pp. 609-620 ◽  
Author(s):  
Dana H. Abdeen ◽  
Bruce R. Palmer

Purpose This paper aims to study the effect of processing parameters of an electron beam melting (EBM) machine on the surface roughness, critical pitting temperature and density of Ti-6Al-4V parts produced from the EBM machine. Design/methodology/approach In this study, statistically designed experiments were used to manufacture Ti-6Al-4V samples in the EBM machine under different process parameters of beam current, beam speed and offset focus. Surface roughness was measured for as-built samples using a 3D profilometer. Then, a potentiostatic test was conducted under 2.40 V vs saturated calomel electrode to determine the critical pitting temperature (CPT) in 3.5 per cent mass NaCl solution for the samples of different processing parameters. Next, density was measured for these samples. Finally, model equations were established to relate EBM’s process parameters to measured properties of surface roughness, CPT and density. Findings Results showed that offset focus had the main influence on surface roughness more than the beam current and the beam speed. Changing processing parameters did not affect corrosion behavior of EBM Ti-6Al-4V as CPT did not vary widely, although a slight effect on CPT values obtained from the beam current and the beam speed. Density was greatly affected by the offset focus more than the other parameters. It can be concluded that uniform and precise measurements of roughness and density are not achievable through this machine; only a range of these properties can be attained. Originality/value EBM machine produces 3D parts in a layer-based building process under high temperature and vacuum atmosphere. Due to the manufacturing technique and conditions, the resulting object has irregularities on the exterior surface and voids that are formed within the part, both of which affect samples’ properties like surface roughness, CPT and density. This study established model equations that can relate parts’ properties to processing parameters so that parts of specific properties are obtained to fit the application they are used for. For each property, ANOVA fits vs linear energy were also obtained.

2016 ◽  
Vol 22 (2) ◽  
pp. 322-329 ◽  
Author(s):  
Dana H. Abdeen ◽  
Bruce R. Palmer

Purpose This paper aims to evaluate the corrosion behavior of Ti-6Al-4V parts produced with electron beam melting (EBM) machine and compare it with wrought Ti-6Al-4V alloy. Design/methodology/approach Potentiodynamic and potentiostatic tests were applied on EBM Ti-6Al-4V in 3.5 per cent mass NaCl solution to determine the pitting potential and critical pitting temperature (CPT). A relation between pitting potential and temperature was established for EBM Ti-6Al-4V alloy by conducting potentiodynamic testing under different temperatures. CPT was also measured for EBM Ti-6Al-4V alloy in 3.5 per cent mass NaCl solution at a standard potential of 800 mV vs saturated calomel electrode (SCE). The same tests were performed on wrought Ti-6Al-4V for comparison purposes. Moreover, CPT for EBM Ti-6Al-4V alloy was measured in 3.5 per cent mass NaCl solution of different pH of 2.0, 5.7 and 10.0 to examine the effect of aggressive conditions on the pitting corrosion of EBM alloy. Findings Potentiodynamic test resulted in a relatively high pitting potential of EBM alloy, which was close to the pitting potential of wrought alloy even at higher temperatures. In addition, EBM samples did not pit when potentiostatic test was performed at 800 mV vs SCE, even at high and low values of pH. Originality/value EBM Ti-6Al-4V alloy has been increasingly playing an important role in aerospace, automobile and industrial fields. The technique and conditions of manufacturing form voids and increase roughness of the exterior surface of EBM objects, which might increase the tendency to initiate pitting corrosion within its holes and surface folds. This article shows that, despite surface variations and porosity in EBM Ti-6Al-4V alloy, the material maintained its corrosion resistance. It was found that the corrosion behavior of EBM alloy was close to that of the conventionally made wrought Ti-6Al-4V alloy.


2016 ◽  
Vol 22 (3) ◽  
pp. 495-503 ◽  
Author(s):  
Rebecca Klingvall Ek ◽  
Lars-Erik Rännar ◽  
Mikael Bäckstöm ◽  
Peter Carlsson

Purpose The surface roughness of products manufactured using the additive manufacturing (AM) technology of electron beam melting (EBM) has a special characteristic. Different product applications can demand rougher or finer surface structure, so the purpose of this study is to investigate the process parameters of EBM to find out how they affect surface roughness. Design/methodology/approach EBM uses metal powder to manufacture metal parts. A design of experiment plan was used to describe the effects of the process parameters on the average surface roughness of vertical surfaces. Findings The most important electron beam setting for surface roughness, according to this study, is a combination of “speed and current” in the contours. The second most important parameter is “contour offset”. The interaction between the “number of contours” and “contour offset” also appears to be important, as it shows a much higher probability of being active than any other interaction. The results show that the “line offset” is not important when using contours. Research limitations/implications This study examined “contour offset”, “number of contours”, “speed in combination with current” and “line offset”, which are process parameters controlling the electron beam. Practical implications The surface properties could have an impact on the product’s performance. A reduction in surface processing will not only save time and money but also reduce the environmental impact. Originality/value Surface properties are important for many products. New themes containing process parameters have to be developed when introducing new materials to EBM manufacturing. During this process, it is very important to understand how the electron beam affects the melt pool.


Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1211 ◽  
Author(s):  
Wadea Ameen ◽  
Muneer Khan Mohammed ◽  
Abdulrahman Al-Ahmari

The addition of support structures is essential for the successful fabrication of overhang structures through additive manufacturing (AM). The support structures protect the overhang portion from distortions. They are fabricated with the functional parts and are removed later after the fabrication of the AM part. While structures bearing insufficient support result in defective overhangs, structures with excessive support result in higher material consumption, time and higher post-processing costs. The objective of this study is to investigate the effects of design and process parameters of support structures on support removability during the electron beam melting (EBM)-based additive manufacturing of the Ti6Al4V overhang part. The support design parameters include tooth parameters, no support offset, fragmentation parameters and perforation parameters. The EBM process parameters consist of beam current, beam scan speed and beam focus offset. The results show that both support design and process parameters have a significant effect on support removability. In addition, with the appropriate selection of design and process parameters, it is possible to significantly reduce the support removal time and protect the surface quality of the part.


2017 ◽  
Vol 23 (3) ◽  
pp. 474-485 ◽  
Author(s):  
Ashfaq Mohammad ◽  
Abdurahman Mushabab Al-Ahmari ◽  
Abdullah AlFaify ◽  
Muneer Khan Mohammed

Purpose Electron beam melting (EBM) is one of the potential additive manufacturing technologies to fabricate aero-engine components from gamma titanium aluminide (γ-TiAl) alloys. When a new material system has to be taken in to the fold of EBM, which is a highly complex process, it is essential to understand the effect of process parameters on the final quality of parts. This paper aims to understand the effect of melting parameters on top surface quality and density of EBM manufactured parts. This investigation would accelerate EBM process development for newer alloys. Design/methodology/approach Central composite design approach was used to design the experiments. In total, 50 specimens were built in EBM with different melt theme settings. The parameters varied were surface temperature, beam current, beam focus offset, line offset and beam speed. Density and surface roughness were selected as responses in the qualifying step of the parts. After identifying the parameters which were statistically significant, possible reasons were analyzed from the perspective of the EBM process. Findings The internal porosity and surface roughness were correlated to the process settings. Important ones among the parameters are beam focus offset, line offset and beam speed. By jointly deciding the total amount of energy input for each layer, these three parameters played a critical role in internal flaw generation and surface evolution. Research limitations/implications The range selected for each parameter is applicable, in particular, to γ-TiAl alloy. For any other alloy, the settings range has to be suitably adapted depending on physical properties such as melting point, thermal conductivity and thermal expansion co-efficient. Practical implications This paper demonstrates how melt theme parameters have to be understood in the EBM process. By adopting a similar strategy, an optimum window of settings that give best consolidation of powder and better surface characteristics can be identified whenever a new material is being investigated for EBM. This work gives researchers insights into EBM process and speeds up EBM adoption by aerospace industry to produce critical engine parts from γ-TiAl alloy. Originality/value This work is one of the first attempts to systematically carry out a number of experiments and to evaluate the effect of melt parameters for producing γ-TiAl parts by the EBM process. Its conclusions would be of value to additive manufacturing researchers working on γ-TiAl by EBM process.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3603
Author(s):  
Tim Pasang ◽  
Benny Tavlovich ◽  
Omry Yannay ◽  
Ben Jakson ◽  
Mike Fry ◽  
...  

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shimin Dai ◽  
Hailong Liao ◽  
Haihong Zhu ◽  
Xiaoyan Zeng

Purpose For the laser powder bed fusion (L-PBF) technology, the side surface quality is essentially important for industrial applicated parts, such as the inner flow parts. Contour is generally adopted at the parts’ outline to enhance the side surface quality. However, the side surface roughness (Ra) is still larger than 10 microns even with contour in previous studies. The purpose of this paper is to study the influence of contour process parameters, laser power and scanning velocity on the side surface quality of the AlSi10Mg sample. Design/methodology/approach Using L-PBF technology to manufacture AlSi10Mg samples under different contour process parameters, use a laser confocal microscope to capture the surface information of the samples, and obtain the surface roughness Ra and the maximum surface height Rz of each sample after analysis and processing. Findings The results show that the side surface roughness decreases with the increase of the laser power at the fixed scanning velocity of 1,000 mm/s, the side surface roughness Ra stays within the error range as the contour velocity increases. It is found that the Ra increases with the scanning velocity increasing and the greater the laser power with the greater Ra increases when the laser power of contour process parameters is 300 W, 350 W and 400 W. The Rz maintain growth with the contour scanning velocity increasing at constant laser power. The continuous uniform contour covers the pores in the molten pool of the sample edge and thus increase the density of the sample. Two mechanisms named “Active adhesion” and “Passive adhesion” cause sticky powder. Originality/value Formation of a uniform and even contour track is key to obtain the good side surface quality. The side surface quality is determined by the uniformity and stability of the contour track when the layer thickness is fixed. These research results can provide helpful guidance to improve the surface quality of L-PBF manufactured parts.


2019 ◽  
Vol 71 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Aqib Mashood Khan ◽  
Muhammad Jamil ◽  
Ahsan Ul Haq ◽  
Salman Hussain ◽  
Longhui Meng ◽  
...  

Purpose Sustainable machining is a global consensus and the necessity to cope up the serious environmental threats. Minimum quantity lubrication (MQL) and nanofluids-based MQL(NFMQL) are state-of-the-art sustainable lubrication modes. The purpose of this study is to investigate the effect of process parameters, such as feed rate, depth of cut and cutting fluid flow rate, on temperature and surface roughness of the manufactured pieces during face milling of the AISI D2 steel. Design/methodology/approach A statistical technique called response surface methodology with Box–Behnken Design was used to design experimental runs, and empirical modeling was presented. Analysis of variance was carried out to evaluate the model’s accuracy and the validation of the applied technique. Findings A comprehensive analysis revealed the superiority of implementing NFMQL in comparison to MQL within the levels of process parameters. The comparison has shown a significant reduction of temperature under NFMQL at the tool-workpiece interface from 16.2 to 34.5 per cent and surface roughness from 11.3 to 12 per cent. Practical implications This research is useful for practitioners to predict the responses in workshop and select appropriate cutting parameters. Moreover, this research will be helpful to reduce the resource which will ultimately save energy consumption and cost. Originality/value To cope with the industrial challenges and tribological issues associated with the milling of AISI D2 steel, experiments were conducted in a distinct machining mode with innovative cooling/lubrication. Until now, few studies have addressed the key lubrication effects of Al2O3-based nanofluid on the machinability of D2 steel under NFMQL lubrication condition.


2010 ◽  
Vol 34-35 ◽  
pp. 1516-1520
Author(s):  
Hong Ye ◽  
Han Li Yang ◽  
Zhong Lin Yan

Electron beam welding process of AZ61 with 10mm thickness magnesium alloys was investigated. The influence of processing parameters including focusing current, welding beam current and welding speed was researched. The results show that an ideal weld bead can be formed by choosing processing parameters properly. Focusing current is main parameter that determines cross section shape. The beam current and welding speed are main parameters that determine the weld width and dimensions. The test results for typical welds indicate that the microhardness of the weld zone is better than that of the base meta1. A fine-grained weld region has been observed and no obvious heat-affected zone is found. The fusion zone mainly consists of small α-Mg phase and β-Mg17A112. The small grains and β phases in the joint are believed to play an important role in the increase of the strength of weld for AZ61 magnesium alloys.


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