TY - JOUR
T1 - Role of microstructure heterogeneity on deformation behaviour in additive manufactured Ti-6Al-4V
AU - Cao, Sheng
AU - Meng, Liju
AU - Liu, Hongyu
AU - Zou, Yichao
AU - Smith, Albert
AU - Wu, Xinhua
AU - Donoghue, Jack
AU - Thomas, Rhys
AU - Preuss, Michael
AU - Lunt, David
N1 - Funding Information:
S.C. thanks the financial support from the National Natural Science Foundation of China (Grant No. 52204391 ), the 2021 Guangdong Province Science and Technology Special Fund Project (Grant No. STKJ2021025 ) and Shantou University Research Foundation for Talents (Grant No. NTF21013 ); Y.Z. thanks the financial support from the National Natural Science Foundation of China (Grant No. 12104517 ) and the ‘100 Top Talents Program’ of Sun Yat-sen University (Grant No. 29000–18841290 ); the technical support from Dr. Yi Yang is gratefully appreciated. This work was also supported by the Henry Royce Institute for Advanced Materials, funded through EPSRC grants EP/R00661X/1, EP/S019367/1, EP/P025021/1 and EP/P025498/1. The authors would also like to thank Dr Michael Atkinson and Professor João Quinta da Fonseca for the development of the DefDAP python package. A.S. would like to thank NewTec Scientific and the applications team at TESCAN Brno s.r.o. for their assistance and technical support.
Funding Information:
S.C. thanks the financial support from the National Natural Science Foundation of China (Grant No. 52204391), the 2021 Guangdong Province Science and Technology Special Fund Project (Grant No. STKJ2021025) and Shantou University Research Foundation for Talents (Grant No. NTF21013); Y.Z. thanks the financial support from the National Natural Science Foundation of China (Grant No. 12104517) and the ‘100 Top Talents Program’ of Sun Yat-sen University (Grant No. 29000–18841290); the technical support from Dr. Yi Yang is gratefully appreciated. This work was also supported by the Henry Royce Institute for Advanced Materials, funded through EPSRC grants EP/R00661X/1, EP/S019367/1, EP/P025021/1 and EP/P025498/1. The authors would also like to thank Dr Michael Atkinson and Professor João Quinta da Fonseca for the development of the DefDAP python package. A.S. would like to thank NewTec Scientific and the applications team at TESCAN Brno s.r.o. for their assistance and technical support.
Publisher Copyright:
© 2022
PY - 2022/12
Y1 - 2022/12
N2 - The influence of two different bi-lamellar microstructures, with varied volume fractions of primary alpha lamellae (αp) and secondary alpha lamellae (αs), on the mechanical performance of laser powder bed fusion fabricated Ti-6Al-4V has been investigated. A low and high αp volume fraction variant was created by different solution heat treatment temperatures. Scanning transmission electron microscopy (STEM) was performed on both materials to give a comprehensive assessment of the local microstructure and element partitioning effects. Deformation experiments, combined with high resolution digital image correlation (HRDIC), enabled a detailed comparison of 2D slip patterns at progressive strain increments during tensile loading, with the underlying microstructure collected using electron backscattering diffraction based grain orientation mapping. In both microstrural variants, shear strain was mainly observed in the coarse αp lamellae, suggesting that the constituent was softer than the fine αs regions. This strength difference is not attributed to potential different levels of Al-based solid solution strengthening as a result of element partitioning. Instead, the strength difference was attributed to the fine β ligaments formed in-between the αs during ageing. The low αp volume fraction variant, i.e. high-volume fraction of αs, displayed a significant increase in yield strength compared to the high αp volume fraction variant without compromising ductility through increased heterogeneous plasticity and an enhanced strain hardening rate.
AB - The influence of two different bi-lamellar microstructures, with varied volume fractions of primary alpha lamellae (αp) and secondary alpha lamellae (αs), on the mechanical performance of laser powder bed fusion fabricated Ti-6Al-4V has been investigated. A low and high αp volume fraction variant was created by different solution heat treatment temperatures. Scanning transmission electron microscopy (STEM) was performed on both materials to give a comprehensive assessment of the local microstructure and element partitioning effects. Deformation experiments, combined with high resolution digital image correlation (HRDIC), enabled a detailed comparison of 2D slip patterns at progressive strain increments during tensile loading, with the underlying microstructure collected using electron backscattering diffraction based grain orientation mapping. In both microstrural variants, shear strain was mainly observed in the coarse αp lamellae, suggesting that the constituent was softer than the fine αs regions. This strength difference is not attributed to potential different levels of Al-based solid solution strengthening as a result of element partitioning. Instead, the strength difference was attributed to the fine β ligaments formed in-between the αs during ageing. The low αp volume fraction variant, i.e. high-volume fraction of αs, displayed a significant increase in yield strength compared to the high αp volume fraction variant without compromising ductility through increased heterogeneous plasticity and an enhanced strain hardening rate.
KW - Additive manufacturing
KW - Electron backscattering diffraction (EBSD)
KW - High resolution digital image correlation (HRDIC)
KW - Titanium alloys
KW - Transmission electron microscopy (TEM)
UR - http://www.scopus.com/inward/record.url?scp=85147089329&partnerID=8YFLogxK
U2 - 10.1016/j.mtla.2022.101636
DO - 10.1016/j.mtla.2022.101636
M3 - Article
AN - SCOPUS:85147089329
SN - 2589-1529
VL - 26
JO - Materialia
JF - Materialia
M1 - 101636
ER -