Laser powder bed fusion of an engineering intermetallic TiAl alloy

Schimbäck, D.; Braun, J.; Leichtfried, Gerhard; Clemens, Helmut; Mayer, Svea

doi:10.1016/j.matdes.2021.109506

Cited by 23 publications

(11 citation statements)

References 58 publications

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“…[ 7 ] However, most of these investigations were performed on cast [ 8 ] or wrought [ 49 ] material, while only few studies addressed two‐step heat treatments of TNM‐B1 manufactured by means of PBF‐EB/M [ 6 ] or laser powder bed fusion. [ 40 ] In this study, the effect of HIP and subsequent two‐step heat treatments at different solution heat treatment temperatures on microstructure and room temperature tensile properties was investigated.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, the authors were able to achieve homogeneous FL and NL‐γ microstructures after appropriate two‐step heat treatments. [ 40 ]…”

Section: Discussionmentioning

confidence: 99%

“…The application of two-step heat treatments for tailoring the microstructure and mechanical properties of TNM-B1 has been addressed in numerous studies. [6][7][8]40,46,49] Typically, these heat treatments consist of a solution heat treatment step at high temperatures with subsequent rapid cooling, followed by an annealing step in the range of 850 to 900 °C. [7] However, most of these investigations were performed on cast [8] or wrought [49] material, while only few studies addressed two-step heat treatments of TNM-B1 manufactured by means of PBF-EB/M [6] or laser powder bed fusion.…”

Section: Discussionmentioning

confidence: 99%

“…[7,8] Overall, the measured phase transformation temperatures are in good agreement with available literature data. [8,40,41] It should be noted that due to the DSC heating rate of 10 K min À1 , the transition temperatures can be overestimated by up to 10 K compared to equilibrium conditions. [8] Based on the results from DSC, different heat treatment strategies were chosen as specified in Table 2.…”

Section: Heat Treatment Strategymentioning

confidence: 99%

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Influence of Two‐Step Heat Treatments on Microstructure and Mechanical Properties of a β‐Solidifying Titanium Aluminide Alloy Fabricated via Electron Beam Powder Bed Fusion

et al. 2022

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Additive manufacturing technologies, particularly electron beam powder bed fusion (PBF‐EB/M), are becoming increasingly important for the processing of intermetallic titanium aluminides. This study presents the effects of hot isostatic pressing (HIP) and subsequent two‐step heat treatments on the microstructure and mechanical properties of the TNM‐B1 alloy (Ti–43.5Al–4Nb–1Mo–0.1B) fabricated via PBF‐EB/M. Adequate solution heat treatment temperatures allow the adjustment of fully lamellar (FL) and nearly lamellar (NL‐β) microstructures. The specimens are characterized by optical microscopy and scanning electron microscopy (SEM), X‐ray computed tomography (CT), X‐ray diffraction (XRD), and electron backscatter diffraction (EBSD). The mechanical properties at ambient temperatures are evaluated via tensile testing and subsequent fractography. While lack‐of‐fusion defects are the main causes of failure in the as‐built condition, the mechanical properties in the heat‐treated conditions are predominantly controlled by the microstructure. The highest ultimate tensile strength is achieved after HIP due to the elimination of lack‐of‐fusion defects. The results reveal challenges originating from the PBF‐EB/M process, for example, local variations in chemical composition due to aluminum evaporation, which in turn affect the microstructures after heat treatment. For designing suitable heat treatment strategies, particular attention should therefore be paid to the microstructural characteristics associated with additive manufacturing.

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Section: Discussionmentioning

confidence: 99%

“…Thus, the authors were able to achieve homogeneous FL and NL‐γ microstructures after appropriate two‐step heat treatments. [ 40 ]…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Heat Treatment Strategymentioning

confidence: 99%

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Influence of Two‐Step Heat Treatments on Microstructure and Mechanical Properties of a β‐Solidifying Titanium Aluminide Alloy Fabricated via Electron Beam Powder Bed Fusion

et al. 2022

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“…Similar two-step heat treatments consisting of a solution heat treatment at high temperatures with rapid cooling and a subsequent precipitation heat treatment are commonly applied for adjusting the microstructures in titanium aluminides. [23][24][25][26] Details regarding the different specimen conditions are given in Table 2. FC-furnace cooling (%10 K min À1 ).…”

Section: Methodsmentioning

confidence: 99%

Locally Adapted Microstructures in an Additively Manufactured Titanium Aluminide Alloy Through Process Parameter Variation and Heat Treatment

et al. 2022

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Electron beam powder bed fusion (PBF-EB/M) has been attracting great research interest as a promising technology for additive manufacturing of titanium aluminide alloys. However, challenges often arise from the processinduced evaporation of aluminum, which is linked to the PBF-EB/M process parameters. This study applies different volumetric energy densities during PBF-EB/M processing to deliberately adjust the aluminum contents in additively manufactured Ti-43.5Al-4Nb-1Mo-0.1B (TNM-B1) samples. The specimens are subsequently subjected to hot isostatic pressing (HIP) and a two-step heat treatment. The influence of process parameter variation and heat treatments on microstructure and defect distribution are investigated using optical and scanning electron microscopy, as well as X-ray computed tomography (CT). Depending on the aluminum content, shifts in the phase transition temperatures can be identified via differential scanning calorimetry (DSC). It is confirmed that the microstructure after heat treatment is strongly linked to the PBF-EB/M parameters and the associated aluminum evaporation. The feasibility of producing locally adapted microstructures within one component through process parameter variation and subsequent heat treatment can be demonstrated. Thus, fully lamellar and nearly lamellar microstructures in two adjacent component areas can be adjusted, respectively.

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