In Situ Observation of Strain Evolution in Cp-Ti Over Multiple Length Scales

Abstract

The strain evolution in polycrystalline CP-Ti strip under tension was studied in situ and at two length scales using Synchrotron X-ray diffraction. To establish the bulk material behavior, experiments were performed at the Australian Synchrotron facility. Because of the relatively large grain size, discontinuous ''spotty'' Debye ring patterns were observed, and a peak fitting algorithm was developed to determine the individual spot positions with the necessary precision for strain determination. The crystallographic directional dependence of strain anisotropy during the loading cycle was determined. Strain anisotropy and yielding of individual crystallographic planes prior to the macroscopic yield point were further clarified by in situ loading experiments performed at the Advanced Light Source (ALS). The deviatoric strain accumulation and plastic response were mapped on a grain-by-grain basis. The onset of microscopic yielding in the grains was identified and correlated with the relative orientation of the grains with respect to the loading direction.

An Experimental Study on Evolution of Grain‐Scale Stress/Strain and Geometrical Necessary Dislocations in Advanced TA15 Titanium Alloy during Uniaxial Tension Deformation

“…[6] The grain scale stress includes intragranular or intergranular stress and generated at mesoscale resulting from insufficient and inhomogeneous plastic deformation. [7,[9][10][11][12][13][14][15][16][17][18][19] Geometrically necessary dislocations (GNDs) were introduced in gradient of strain field to maintain the geometrical constrains in crystal lattices. In addition, the limitation in technical experiments for stress/strain detection and characterization at grain scale restrict the conduct of studies on grain-scale stress/strain.…”

A Novel Tensile Device for In Situ Scanning Electron Microscope Mechanical Testing

“…The processes of crack initiation, propagation, and deformation until fracture of materials could be researched through in situ testing based on the observation of scanning electron microscope (SEM), atomic force microscope (AFM), X‐ray diffraction, and Raman spectrometer, etc 1,2 . Frequently, the in situ tensile testing is adopted as the primary method to deeply investigate the micromechanical behavior of various materials combined with the engineering stress–strain curve 3 .…”

A Miniaturized In Situ Tensile Platform under Microscope

“…Frequently, the in situ tensile testing could be adopted as primary method to deeply investigate the micro-mechanical behavior of various materials combined with the engineering stress-strain curve [3], [4]. Lawrence Livermore National Laboratory (LINL) and Lawrence Berkeley National Laboratory (LBNL) researched on nanotubes, nanowires and many other specimens with extremely tiny dimensions based on FIB technology under unixial tensile mode [2], [5], [6]. C. J. Bettles [2] of Monash University and D. Q. Zhang [3] of Dalian University of Technology constructed tensile platforms with CCD imaging component respectively.…”

“…Lawrence Livermore National Laboratory (LINL) and Lawrence Berkeley National Laboratory (LBNL) researched on nanotubes, nanowires and many other specimens with extremely tiny dimensions based on FIB technology under unixial tensile mode [2], [5], [6]. C. J. Bettles [2] of Monash University and D. Q. Zhang [3] of Dalian University of Technology constructed tensile platforms with CCD imaging component respectively. In addition, these works were mostly developed based on MEMS technology [6], [7].…”

“…">IntroductionThe processes of crack initiation, propagation, deformation until fracture of materials could be researched via in situ testing based on the observation of SEM, metallographic microscope, X-ray diffraction and Raman spectrometer, etc [1][2][3]. Frequently, the in situ tensile testing could be adopted as primary method to deeply investigate the micro-mechanical behavior of various materials combined with the engineering stress-strain curve In situ tensile testing based on AFM was also frequently selected, such as T. Nishino [4] of Kobe University developed a device based on the functions of manual and automatic adjustment for the tensile testing of PET film material.…”