Two-Dimensional Time-Resolved X-ray Diffraction Study of Directional Solidification in Steels

Abstract

In situ characterization of directional solidification process during welding was carried out using the time resolved X-ray diffraction technique utilizing intense synchrotron radiation. Then, behaviour of dendrites in steels under welding conditions of a practical manufacturing process were investigated using the TRXRD method for in-situ weld observation with the uniquely-sensitive two-dimensional pixel detector. Consequently, the crystal growth during the rapid cooling was caught in detail and employed a systematic peak profile analysis in order to acquire the essential information for controlling the weld microstructure. Our results would suggest the microstructure formation process of low alloy in directional solidification during rapid cooling. Simultaneously, we discuss the possibility of detecting the nucleation.

Revisiting the Structure of Martensite in Iron-Carbon Steels

“…The rapid cooling is a result of the heat absorption by the cold steel adjoining the molten weld leading to rates as high as several hundred C s À1 . 14) The experimental observations of Yonemura et al provided in situ diffraction patterns of the phase transformation process during rapid weld cooling. The experimental procedure was possible because of the availability of intense X-ray beams from synchrotron storage rings.…”

“…Yonemura et al 14,15) have studied changes in the structure of Fe-C steels as they solidify from the molten state during welding. Their work involves in situ measurements taken using a time-resolved, X-ray diffraction technique as pioneered by Babu et al 16,17) and Elmer et al 18) The uniqueness and value of the Yonemura et al study is the use of a very fast detector with very fine time resolution for capturing individual diffraction peaks during quenching.…”

“…What structural changes, if any, occur during the approximate 500 C drop in temperature from the start of the equilibrium transformation temperature (723-750 C) to the M S temperature? The recent work of Yonemura et al 14,15) provides clues to answer this question. In this work, in situ observations of the structural changes during quenching of an Fe-0.88 mass% C steel were made with time-resolved X-ray diffraction.…”

High‐temperature laser‐scanning confocal microscopy as a tool to study the interface instability during unsteady‐state solidification of low‐carbon steel

“…Succinonitrile solidifies at about 329K, which simplifies the study of solidification phenomena, but the question remains as to what extend such solidification studies replicate the solidification behaviour of steel. Sen et al (1997) and more recently Yonemura et al (2006) suggested the use of X-ray transmission microscopy to study the solid/liquid interface during the solidification of metals, but they were unable to observe the evolution of the interface.…”

<i>In Situ</i> and Real-Time Observation of the Solidification Process of Al&ndash;20 mass%Cu Alloy by Synchrotron X-ray Radiography

“…1,2) In general, the final microstructures of the casting are the result of the competition between the growth of an outer columnar (oriented properties) and an inner equiaxed (isotropic properties) grains. 3) Traditionally, most previous studies of the microstructure have relied on the post-solidification, optically transparent materials and computer simulation.…”