Analysis of heat-affected zone phase transformations using in situ spatially resolved x-ray diffraction with synchrotron radiation
- Lawrence Livermore National Lab., CA (United States)
- Grand Canyon Univ., Phoenix, AZ (United States). Coll. of Science and Allied Health
Spatially resolved X-ray diffraction (SRXRD) consists of producing a submillimeter size X-ray beam from an intense synchrotron radiation source to perform real-time diffraction measurements on solid materials. This technique was used int his study to investigate the crystal phases surrounding a liquid weld pool in commercial purity titanium and to determine the location of the phase boundary separating the high-temperature body-centered-cubic (bcc) {beta} phase from the low-temperature hexagonal-close-packed (hcp) {alpha} phase. The experiments were carried out at the Stanford Synchrotron Radiation Laboratory (SSRL) using a 0.25 x 0.50 mm X-ray probe that could be positioned with 10-{micro}m precision on the surface of a quasistationary gas tungsten arc weld (GTAW). The SRXRD results showed characteristic hcp, bcc, and liquid diffraction patterns at various points along the sample, starting from the base metal through the heat-affected zone (HAZ) and into the weld pool, respectively. Analyses of the SRXRD data show the coexistence of bcc and hcp phases in the partially transformed (outer) region of the HAZ and single-phase bcc in the fully transformed (inner) region of the HAZ. Postweld metallographic examinations of the HAZ, combined with a conduction-based thermal model of the weld, were correlated with the SRXRD results. Finally, analysis of the diffraction intensities of the hcp and bcc phases was performed on the SRXRD data to provide additional information about the microstructural conditions that may exist in the HAZ at temperature during welding. This work represents the first direct in situ mapping of phase boundaries in fusion welds.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 230723
- Journal Information:
- Metallurgical Transactions, A, Vol. 27, Issue 3; Other Information: PBD: Mar 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
In-situ spatially resolved x-ray diffraction mapping of the alpha to beta to alpha transformation in commercially pure titanium arc welds
Investigation of real-time microstructure evolution in steep thermal gradients using in-situ spatially resolved X-ray diffraction: A case study for Ti fusion welds