Xipeng Tan, Yihong Kok, Yu Jun Tan, Guglielmo Vastola, Qing Xiang Pei, Gang Zhang, Yong-Wei Zhang, Shu Beng Tor, Kah Fai Leong, Chee Kai Chua, An experimental and simulation study on build thickness dependent microstructure for electron beam melted Ti–6Al–4V, Journal of Alloys and Compounds, Volume 646, 15 October 2015, Pages 303-309, ISSN 0925-8388, http://dx.doi.org/10.1016/j.jallcom.2015.05.178.
Abstract:
Build thickness dependent microstructure of electron beam melted (EBM®) Tie6Ale4V has been
investigated from both experiment and simulation using four block samples with thicknesses of 1, 5, 10
and 20 mm. We observe a mixed microstructure of alternate a/b with some a0 martensite inside the
1 mm-thick sample. By contrast, only the alternate a/b microstructure with both colony and basket-
weave morphologies occurs inside the 5 mm-, 10 mm- and 20 mm-thick samples. It is found that b
spacing is constantly increased with the build thickness, leading to an obvious decrease in microhard-
ness. Finite element method (FEM) simulations show that cooling rates and thermal profiles during EBM
process are favorable for the formation of martensite. Moreover, full-scale FEM simulations reveal that
the average temperature inside the samples is higher as the build thickness increases. It suggests that
martensitic decomposition is faster in thicker samples, which is in good agreement with the experi-
mental observations.