Papers by Author: Z.H. Jiang

Abstract: Orthogonal experiments of milling titanium alloy TA12 were done on the lifting workbench milling machine. The milling force signals were acquired through PIC-1712 Data Acquired Board. The main frequencies and energy distribution were got through analysis in SPTOOL of MATLAB. The signals were decomposed and reconstructed based on the main frequency of the milling force with wavelet toolbox. The influence of the milling velocity, axial depth of cut and radial depth of cut on the component milling force was got through range analysis. Through analyzing known that three factors had different influence on the component milling force.

Abstract: Nanocrystalline (NC) metals and alloys always exhibit extremely high strength but quite limited ductility. This disappointing ductility might be caused by the preparation artifacts and the weak strain hardening ability of NC materials. In order to optimize the mechanical properties of NC metals and alloys , especially to enhance their ductility, and investigate the underlying deformation mechanism, nanocrystalline Ni, dual phase Ni-Co alloy and Cu were synthesized via electrodeposition and electro-brush deposition respectively, and then a series of mechanical tests were carried out. The results show that all the materials exhibit a combination of high strength and remarkable ductility. The high strength can be attributed to the “true” nanocrystalline grain sizes ranges from 15 to 30 nm. In addition, three factors are revealed to contribute to the enhanced ductility of these materials, respectively: (a) modified deformation mode (the tensile-relaxation cycle test) for nanocrystalline Ni, (b) high strain hardening and cooperative deformation for dual-phase Ni-Co alloy, and (c) high strain rate sensitivity for nanocrystalline Cu.