Control of grain structure, phases, and defects in additive manufacturing of high-performance metallic components

Mukherjee, T.; Elmer, J. W.; Wei, Huiliang; Lienert, Thomas J.; Zhang, Wei; Kou, Sindo; DebRoy, T.

doi:10.1016/j.pmatsci.2023.101153

Cited by 79 publications

(13 citation statements)

References 561 publications

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“…The solidification microstructure of the LPBF-fabricated metallic materials depends highly on the undercooling ∆T ahead of solid/liquid (S/L) interface [46,79]. For pure metals, solidification occurs with a stable planar interface.…”

Section: Effect Of Solution Treatment On Microstructuresmentioning

confidence: 99%

Effect of solution treatment on the microstructure, phase transformation behavior and functional properties of NiTiNb ternary shape memory alloys fabricated via laser powder bed fusion in-situ alloying

Xi,

Jiang,

et al. 2024

Int. J. Extrem. Manuf.

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Post-heat treatment is commonly employed to improve the microstructural homogeneity and enhance the mechanical properties of the additively manufactured metallic materials. In this work, a ternary (NiTi)91Nb9 (at.%) shape memory alloy was fabricated by laser powder bed fusion (L-PBF) using pre-alloyed NiTi and elemental Nb powders. The influence of solution treatment on the microstructure, phase transformation behaviour and mechanical/functional properties was investigated. The in-situ alloyed (NiTi)91Nb9 alloy exhibits a submicron cellular-dendritic structure surrounding the supersaturated B2-NiTi matrix. Upon high-temperature (1273K) solution treatment, Nb-rich precipitates are precipitated from the supersaturated matrix. The fragmentation and spheroidization of the NiTi/Nb eutectics occur during solution treatment, leading to a morphological transition from mesh-like into rod-like and sphere-like. Coarsening of the β-Nb phases occurs with increasing holding time. The martensite transformation temperature increases after solution treatment, mainly attributed to (i) reduced lattice distortion caused by the expulsion of Nb from the supersaturated matrix and (ii) the expulsion of Ti from the β-Nb phases that lowers the Ni/Ti ratio of the matrix, which resulted from the microstructure changes from non-equilibrium to equilibrium state. The thermal hysteresis of the solutionized alloys is around 145 K after 20% pre-deformation, which is comparable to the conventional NiTiNb alloys. A short-term solution treatment (i.e., at 1273K for 30 min) improves the strength and ductility of the as-printed alloy, with the fracture stress increases from 613±19 MPa to 781±20MPa and the fracture strain increases from 7.6±0.1% to 9.5±0.4%. Both the as-printed and solutionized samples exhibit good shape memory effects with shape recovery rates >90%.

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Section: Effect Of Solution Treatment On Microstructuresmentioning

confidence: 99%

Effect of solution treatment on the microstructure, phase transformation behavior and functional properties of NiTiNb ternary shape memory alloys fabricated via laser powder bed fusion in-situ alloying

Xi,

Jiang,

et al. 2024

Int. J. Extrem. Manuf.

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“…In this case, the rapid solidification process of liquid-solid phase transformation during LPBF occurs at extremely high cooling rates, typically exceeding 10 6 K s −1 [19]. Consequently, non-equilibrium solidification microstructures are formed under significantly large subcooling and high grain growth rates, resulting in increased solute solid solubility, much smaller grain size compared with conventionally processed counterparts, and reduced element segregation [20]. For instance, Wang et al [21] observed that the grain size of LPBF-printed pure Zn was approximately 10 µm compared to hundreds of microns for casted Zn.…”

Section: Introductionmentioning

confidence: 99%

Role of heterogenous microstructure and deformation behavior in achieving superior strength-ductility synergy in zinc fabricated via laser powder bed fusion

Dong,

Han,

Zhao

et al. 2024

Int. J. Extrem. Manuf.

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Zinc (Zn) is considered a promising biodegradable metal for implant applications due to its appropriate degradability and favorable osteogenesis properties. In this work, laser powder bed fusion (LPBF) additive manufacturing was employed to fabricate pure Zn with a heterogenous microstructure and exceptional strength-ductility synergy. An optimized processing window of LPBF was established for printing Zn samples with relative densities greater than 99% using a laser power range of 80–90 W and a scanning speed of 900 mm/s. The Zn sample printed with a power of 80 W at a speed of 900 mm/s exhibited a hierarchical heterogenous microstructure consisting of millimeter-scale molten pool boundaries, micrometer-scale bimodal grains, and nanometer-scale pre-existing dislocations, due to rapid cooling rates and significant thermal gradients formed in the molten pools. The printed sample exhibited the highest ductility of ~12.1% among all reported LPBF-printed pure Zn to date with appreciable ultimate tensile strength (~128.7 MPa). Such superior strength-ductility synergy can be attributed to the presence of multiple deformation mechanisms that are primarily governed by heterogeneous deformation-induced hardening resulting from the alternatively arrangement of bimodal Zn grains with pre-existing dislocations. Additionally, continuous strain hardening was facilitated through the interactions between deformation twins, grains and dislocations as strain accumulated, further contributing to the superior strength-ductility synergy. These findings provide valuable insights into the deformation behavior and mechanisms underlying exceptional mechanical properties of LPBF-printed Zn and its alloys for implant applications.

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“…• Common steels and alloys of nickel, titanium, aluminium, and copper are not designed to withstand rapid cooling, repeated thermal cycles, large temperature gradients, and fluctuating stresses during AM. Therefore, they often do not provide optimum microstructures and properties and suffer from defects [5]. New alloys, especially tailored for AM, are being developed primarily based on thermodynamic and kinetic approaches.…”

Section: Introductionmentioning

confidence: 99%

“…External fields such as ultrasounds, magnetic fields, electric fields, and auxiliary heating are applied to improve microstructure and reduce defects [4]. Since the microstructure and properties of printed parts vary widely depending on the process and alloy used, there is no definitive single pathway for controlling them [5]. Ongoing efforts include developing a comprehensive knowledge base for understanding microstructural features and how they are related to multiple properties for a wide variety of engineering alloys. Common steels and alloys of nickel, titanium, aluminium, and copper are not designed to withstand rapid cooling, repeated thermal cycles, large temperature gradients, and fluctuating stresses during AM.…”

Section: Introductionmentioning

confidence: 99%

“…Ongoing efforts include developing a comprehensive knowledge base for understanding microstructural features and how they are related to multiple properties for a wide variety of engineering alloys. Common steels and alloys of nickel, titanium, aluminium, and copper are not designed to withstand rapid cooling, repeated thermal cycles, large temperature gradients, and fluctuating stresses during AM. Therefore, they often do not provide optimum microstructures and properties and suffer from defects [5]. New alloys, especially tailored for AM, are being developed primarily based on thermodynamic and kinetic approaches. Residual stresses, distortion, and common defects such as porosity, cracking, surface roughness, and lack of fusion significantly affect the mechanical properties, quality, reliability, and serviceability of printed parts [4].…”

Section: Introductionmentioning

confidence: 99%

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Recent progress in process, structure, properties, and performance in additive manufacturing

Mukherjee

2023

Science and Technology of Welding and Joining

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The similarities between additive manufacturing (AM) and fusion welding have made Science and Technology of Welding and Joining an appropriate venue to discuss the recent progress made in AM. This special issue highlights significant recent progress in AM towards inventing new processes, developing novel materials, improving microstructure, achieving unique mechanical properties, and reducing defects. Furthermore, it identifies the modern tools of the digital age such as mechanistic modelling, machine learning, and digital twin as powerful drivers of this progress. The articles in this special issue are also believed to identify research needs and opportunities for the AM community.

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Control of grain structure, phases, and defects in additive manufacturing of high-performance metallic components

Cited by 79 publications

References 561 publications

Effect of solution treatment on the microstructure, phase transformation behavior and functional properties of NiTiNb ternary shape memory alloys fabricated via laser powder bed fusion in-situ alloying

Effect of solution treatment on the microstructure, phase transformation behavior and functional properties of NiTiNb ternary shape memory alloys fabricated via laser powder bed fusion in-situ alloying

Role of heterogenous microstructure and deformation behavior in achieving superior strength-ductility synergy in zinc fabricated via laser powder bed fusion

Recent progress in process, structure, properties, and performance in additive manufacturing

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