Abstract: The effect of building direction on the dynamic deformation behavior of electron beam melted Ti- 6Al-4V alloy was investigated. Several dynamic compression tests were performed at strain rates varying from 150 s-1 to 2200 s-1 using a split-Hopkinson pressure bar apparatus. The maximum stress increased as the strain rate increased up to a peak value. It then dropped with further increase of the strain rate for horizontally and vertically printed samples. Under similar loading conditions, the strength of vertically printed specimens was consistently higher than that of the horizontal ones, which can be attributed to the finer microstructure of the vertically printed samples. The dynamic yield strength of the alloy in both directions was strain rate dependent, where the maximum of 2046 MPa was attained in the vertically printed sample at 1500 s-1. In horizontal samples, failure occurred beyond 2200 s-1, whereas fracture initiated at much lower strain rates of about 1300 s-1 in vertical samples.
Authors: R. Alaghmandfard, C. Dharmendra, A. Odeshi, and M. Mohammadi
Keywords: Ti-6Al-4V, Electron beam melting (EBM), SHPB, High strain rate, Dynamic behavior, microstructure