Progress of Ultra-high Temperature Oxide Ceramics: Laser Additive Manufacturing and Microstructure Evolution

doi:10.15541/jim20230560

Abstract

Abstract:

Oxide ceramics, known for their outstanding strength and excellent oxidation and corrosion resistance, are prime candidates for high-temperature structural materials of aero-engines. These materials hold vast potential for application in high-end equipment fields of the aerospace industry. Compared with traditional ceramic preparation methods, laser additive manufacturing (LAM) can directly realize the integrated forming from raw powders to high-performance components in one step. LAM stands out for its high forming efficiency and good flexibility, enabling rapid production of large complex structural components with high performance and high precision. Recently, research on LAM for melt-grown oxide ceramics, which involves liquid-solid phase transition, has surged as a hot topic. This paper begins by outlining the basic principles of LAM technology, with an emphasis on the process characteristics of two typical LAM technologies: selective laser melting and laser directed energy deposition. On this basis, the paper summarizes the microstructure characteristics of several different oxide ceramics prepared by LAM and examines how process parameters influence these microstructures. The differences in mechanical properties of laser additive manufactured oxide ceramics with different systems are also summarized. Finally, the existing problems in this field are sorted out and analyzed, and the future development trend is prospected.

Key words: ultra-high temperature oxide ceramic, laser additive manufacturing, selective laser melting, laser directed energy deposition, microstructure evolution, review

CLC Number:

TQ174

CHEN Qian, SU Haijun, JIANG Hao, SHEN Zhonglin, YU Minghui, ZHANG Zhuo. Progress of Ultra-high Temperature Oxide Ceramics: Laser Additive Manufacturing and Microstructure Evolution[J]. Journal of Inorganic Materials, 2024, 39(7): 741-753.

Figures/Tables 14

Table 1 Lasers for LAM and their characteristics[19]

Laser type	CO₂ laser	Nd: YAG laser	Yb-fiber laser
Wavelength/μm	10.6	1.06	1.07
Efficiency/%	5-20	1-3	10-30
Output power/kW	~20	~16	~10
Beam quality factor	3-5	0.4-20	0.3-4
Preferred material	Ceramic/polymer	Metal	Metal

Fig. 1 Principle of selective laser melting (SLM) and as-prepared oxide ceramic samples (a) Schematic diagram[22]; (b) ZrO2 ceramic[23]; (c) Al2O3/GAP eutectic ceramic[24]; (d) Al2O3/GAP/ZrO2 eutectic ceramic[25]

Fig. 2 Principle of laser directed energy deposition (LDED) and as-prepared oxide ceramic samples (a) Schematic diagram[26]; (b) Al2O3/ GdAlO3/ZrO2 eutectic ceramic with complex structure[29]; (c) Graded Al2O3/ZrO2 eutectic ceramic[31]; (d) Rod-like Al2O3/GdAlO3/ZrO2 eutectic ceramic[30]

Table 2 Comparison of process characteristics of SLM and LDED[32]

Process	Preferred laser	Power/W	Building rate / (cm³·min^-1)	Dimensional accuracy/mm	Surface roughness/μm	Application
SLM	Nd: YAG laser/fiber laser	50-1000	1.3	0.04-0.2	7-20	High precision and small scale component
LDED	CO₂ laser	100-3000	11.5	0.5-1.0	4-10	Large scale component

Fig. 3 Microstructures of single-phase oxide ceramics prepared by LDED (a, b) Cross section (a) and longitudinal section (b) of Al2O3 ceramic[33]; (c, d) Longitudinal section of ZrO2 ceramic (c) and its magnified image (d)[34]

Table 3 Entropy of different phases in eutectic and corresponding growth manner[35-36]

Phase	Entropy/ (J·mol^-1·K^-1)	Jackson factor	Growth manner
Al₂O₃	48	5.74	Faceted
GAP	16.5	1.9	Non-faceted
YAG	122	14.72	Faceted
ZrO₂	30	3.55	Weak faceted

Fig. 4 Typical microstructure morphologies of cross/longitudinal sections of LAM fabricated oxide eutectic ceramics (a) Periodic banded structure and (b) magnified image[42]; (c) Three ways of intersectional dispersion microstructure[36]; (d) Colony structure and (d1, d2) magnified images[36]

Fig. 5 Microstructure of Al2O3/ZrO2 eutectic ceramic and corresponding crystallographic orientation[43] (a) Transversal section; (b) Corresponding EBSD pole figures of Al2O3 and ZrO2 with (b1) EBSD phases and (b2) IPF (inverse pole figure); (c) Transverse sectional TEM (transmission electron microscope) image with (c1) SAED (selected area electron diffraction) and (c2) HRTEM (high-resolution TEM) at Al2O3/ZrO2 interface

Fig. 6 Microstructure and orientation evolution of Al2O3/YAG eutectic ceramic along deposition direction[37] (a) Longitudinal section; (b) Orientation variations of Al2O3 and YAG along the height; (c1, c2) TEM images and SAED patterns of (c1) irregular and (c2) regular eutectic inverse pole figures

Table 4 Crystal orientation relationship of the oxide eutectic ceramics by different preparation methods

Eutectic system	Preparation method	Crystal orientation relationship
Al₂O₃/YAG/ZrO₂	Laser directed energy deposition^[43] Optical floating zone method^[44]	[0001]Al₂O₃∥[001]YAG∥[001]ZrO₂ <11¯00>Al₂O₃∥<001>YAG∥<001>ZrO₂
Al₂O₃/ZrO₂	Laser directed energy deposition^[35] Laser floating zone method^[45]	[112¯0]Al₂O₃∥[001]ZrO₂ [022¯1]Al₂O₃∥[111]ZrO₂
Al₂O₃/YAG	Bridgman^[46] Laser directed energy deposition^[37]	[101¯0]Al₂O₃∥[101]YAG [101¯0]Al₂O₃∥[111]YAG

Fig. 7 Microstructures of Al2O3/ZrO2 parts with different ZrO2 contents[49-50]

Fig. 8 Microstructures at top region of the Al2O3/GAP eutectic ceramics under different scanning rates[36] (a) 4 mm/min; (b) 8 mm/min; (c) 16 mm/min; (d) 30 mm/min

Fig. 9 Micro-morphologies of the Al2O3/ZrO2 eutectic ceramics with different ultrasonic powers[57] (a) 20-50 W; (b) 110 W; (c) 120-150 W; (d) 160 W

Table 5 Comparison of mechanical properties among different oxide ceramics prepared by different LAM technologies

Material	Hardness/GPa	Fracture toughness/(MPa·m^1/2)	Flexural strength/MPa	Preparation method
Al₂O₃	16 18.91	/ 3.55	/ 350	Sintering^[64] LDED^[65]
ZrO₂(Y₂O₃)	19.80	/	/	LDED^[34]
Al₂O₃/ZrO₂	/ 15.3 / 18.59 /	6.03 7.8 / 6.52 7.67/8.70	525 / 538 / /	Sintering^[66] DS^[67] SLM^[68] LDED^[63] LDED (ultrasonic assisted/C fiber)^[57,61]
Al₂O₃/GAP	23.36 17.1 15.16	3.12 4.5 4.3	/ / /	DS^[69] SLM^[36] LDED^[70]
Al₂O₃/TiO₂	16.38	3.75	212	LDED^[47]
Al₂O₃/SiO₂	11.10 18.39 18.64	2.54 3.07 3.54	350 310 504	Sintering^[71] LDED^[52]LDED (heat treatment)^[48]
Al₂O₃/YAG	17.50 17.35 21.50	3.60 3.14 5.86	/ / /	DS^[72] LDED^[73] LDED (water cooling)^[60]
Al₂O₃/GAP/ZrO₂	17.50 17.90 15.30	6.50 8.50 7.80	485 / /	Sintering^[74] DS^[75] SLM^[25]
Al₂O₃/YAG/ZrO₂	15.80 18.90	3.90 3.84	/ /	DS^[76] LDED^[35]

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