Observation of the initiation and propagation of solidification cracks by means ofin situsynchrotron X-ray radiography

Abstract

A 3D coupled hydro-mechanical granular model for the prediction of hot tearing formation M Sistaninia, A B Phillion, J -M Drezet et al.Investigation of gravity effects on solidification of binary alloys with in situ Xray radiography on earth and in microgravity environment H Nguyen-Thi, A Bogno, G Reinhart et al. Abstract. We report on the in situ, time resolved, observation of solidification cracking in a thin sample of an Al-15wt%Sn alloy at ESRF BM05. During the experiment, solidification cracking was seen to occur during natural cooling of the sample at a solid fraction of ∼95%, between directionally agglomerated dendritic networks. Through detailed analysis, three stages of crack growth were observed: crack initiation, which typically occurs asymmetrically with the liquid film separating from one side of the dendritic network prior to full detachment; crack propagation, where the liquid film generally detaches from both sides simultaneously; and crack coalescence. We correlate our observations using scanning electron microscopy, which shows that voids between grains, and also spikes, can appear asymmetrically on either side of the crack surface.

Initiation and growth kinetics of solidification cracking during welding of steel

“…The author later employed a radiography approach20 to observe semi-solid deformation and failure. A similar approach was then employed by Aveson et al 21,. although at a much smaller scale, to observe damage initiation and propagation, at the dendritic scale, in an Al-Sn binary alloy.…”

A Three-Stage Mechanistic Model for Solidification Cracking During Welding of Steel

“…However, nucleation and propagation mechanisms are inconclusive and hindered by a lack of direct experimental observation to validate the theories proposed. Only recently have experimental observations on solidification cracking started to emerge: first for transparent analogues in 2001 and 2002 [11,12] and then aluminum alloys [13][14][15][16][17][18][19][20][21][22] from 2006 to 2017. The following crack nucleation sites have been suggested as a result: 1.…”