In order to improve the high-temperature oxidation resistance and further promote the engineering application of titanium alloy in high temperature and complex service environment conditions
high niobium Ti-Al intermetallic compound oxidation resistance coatings were prepared on BT3-1 titanium alloy surface by laser in situ synthesis process. Microstructure of the composite coating and interface was optimized through a self-designed heat treatment process according to the defects in the coating. The phase structure and microstructure of the coating before and after heat treatment were analyzed by Optical Microscope (OM)
X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The results show that the coating mainly consists of Nb
intermetallic γ-TiAl
α
2
-Ti
3
Al and Ti
3
Al
2
phases before heat treatment. But after heat treatment
the Nb is dissolved in γ-TiAl and α
2
-Ti
3
Al
and new phase Ti
3
AlNb
0.3
is observed in the coating. The microstructure of the coating is approximately γ-TiAl+α
2
-Ti
3
Al biphasic lamellar equiaxed grains structure. Moreover
the element Nb particle and Ti
3
Al
2
phase which weaken inoxidizability are not observed in the coating. The macro segregation of Ti
Al and Nb is eliminated
and the pores or cracks at interface positions between the composite coating and substrate are disappeared. A distinct white band transition metallurgical bonding layer is generated
and the microstructure of the coating is more uniform and dense. Heat treatment plays an important role in improving the Nb alloying extent on titanium alloy surface and increasing the high temperature oxidation resistance of the Ti-Al intermetallic composite coating.
关键词
Keywords
references
YANG Z Y, ZHENG X H, CAI W. Martensitic transformation and shape memory effect of Ti-V-Al lightweight high-temperature shape memory alloys[J]. Scripta Materialia, 2015, 99: 97-100.
WENG F, CHEN C Z, YU H J. Research status of laser cladding on titanium and its alloys: A review[J]. Materials & Design, 2014, 58: 412-425.
CASTILLO-RODRÍ GUEZM, NÓML, JIMÉNEZ J A, et al.. High temperature internal friction in a Ti-46Al-1Mo-0.2Si intermetallic, comparison with creep behaviour[J]. Acta Materialia, 2016, 103: 46-56.
ZHAO ZH W, WANG X Y, YU D Y, et al.. Preparation and properties of titanium clad steel plate with interlayer in laser cladding[J]. Opt. Precision Eng., 2016, 24(10): 12-19. (in Chinese)
SHI J P, ZHOU Y B, LIU L M. Root welding process in laser-TIG hybrid welding of titanium alloy thick plate[J]. Opt. Precision Eng., 2016, 24(10): 280-286. (in Chinese)
SHI Z W, WEI H, ZHANG H Y, et al.. Investigation of a hot-pressed Nb-Ti-Al alloy: Mechanical alloying, microstructure and mechanical property[J]. Materials Science and Engineering: A, 2016, 651: 869-877.
LIU H X, TAO X D, ZHANG X W, et al.. Microstructure and interface distribution of Fe-Cr-Si-B-C laser cladding alloy coatings assisted by mechanical vibration[J]. Opt. Precision Eng., 2015, 23(8): 2192-2202. (in Chinese)
CHEN L, YANG Y, WU M J, et al.. Correlation between arc evaporation of Ti-Al-N coatings and corresponding Ti 0.50 Al 0.50 target types[J]. Surface and Coatings Technology, 2015, 275: 309-315.
LIU H X, ZHANG X W, JIANG Y H, et al.. Microstructure and high temperature oxidation resistance of in-situ synthesized TiN/Ti 3 Al intermetallic composite coatings on Ti 6 Al 4 V alloy by laser cladding process[J]. Journal of Alloys and Compounds, 2016, 670:268-274.
TEPPERNEGG T, ANGERER P, KLVNSNER T, et al.. Evolution of residual stress in Ti-Al-Ta-N coatings on hard metal milling inserts[J]. International Journal of Refractory Metals and Hard Materials, 2015, 52: 171-175.
ABI-TANNOUS T, SOUEIDAN M, FERRO G, et al.. Parametric investigation of the formation of epitaxial Ti 3 SiC 2 on 4H-SiC from Al-Ti annealing[J]. Applied Surface Science, 2015, 347: 186-192.
SHI Z W, WEI H, ZHANG H Y, et al.. Nanotwinned Ti(O, C) induced by oriented attachment in a hot-pressed Nb-Ti-Al alloy[J]. Acta Materialia, 2016, 105: 114-120.
ZHANG D Q, WU J Y, LI B, et al.. Preparation of ceramic membranes on porous Ti-Al alloy supports by an in-situ oxidation method[J]. Journal of Membrane Science, 2015, 476: 554-560.
ZHANG Q, CHEN J, WANG L L, et al.. Solidification microstructure of laser additive manufactured Ti-6Al-2Zr-2Sn-3Mo-1.5Cr-2Nb titanium alloy[J]. Journal of Materials Science & Technology, 2016, 32(4): 381-386.
LI D K, CHEN J F, ZOU C W, et al.. Effects of Al concentrations on the microstructure and mechanical properties of Ti-Al-N films deposited by RF-ICPIS enhanced magnetron sputtering[J]. Journal of Alloys and Compounds, 2014, 609: 239-243.
FAROOQ M U, KHALID F A, ZAIGHAM H, et al.. Superelastic behaviour of Ti-Nb-Al ternary shape memory alloys for biomedical applications[J]. Materials Letters, 2014, 121: 58-61.
陈国良.金属间化合物结构材料研究现状与发展[J].材料导报, 2000, 14(9): 1-5.
CHEN G L. R&D status and prospect on the ordered structural intermetallics[J]. Materials Review, 2000, 14(9): 1-5. (in Chinese)
ZHENG CH L, XU ZH, HE ZH Y, et al.. Progress in research on high temperature oxidation resistance of TiAl intermetallics[J]. Materials Review, 2002, 16(11): 14-16. (in Chinese)
DING X F. Effect of Microstructures on Mechanical Properties for Ti-Al-Nb Ternary Alloys[D]. Dalian: Dalian University of Technology, 2014. (in Chinese)
DIMIDUK D M. Gamma titanium aluminide alloys—an assessment within the competition of aerospace structural materials[J]. Materials Science and Engineering: A, 1999, 263(2): 281-288.
JIANG H R, HIROHASI M, LU Y, et al.. Effect of Nb on the high temperature oxidation of Ti-(0-50 at.%)Al[J]. Scripta Materialia, 2002, 46(9): 639-643.
KOO C H, YU T H. Pack cementation coatings on Ti 3 Al-Nb alloys to modify the high-temperature oxidation properties[J]. Surface and Coatings Technology, 2000, 126(2-3): 171-180.
KENEL C, LEINENBACH C. Influence of Nb and Mo on microstructure formation of rapidly solidified ternary Ti-Al-(Nb, Mo) alloys[J]. Intermetallics, 2016, 69: 82-89.
BAI R, ZHENG X, LI Z K, et al.. Precipitation strengthening mechanism of Nb-Ti-Al alloys[J]. Procedia Engineering, 2012, 27: 1241-1247.