The Isothermal Oxidation Behavior of a Ti3Al-Nb-V-Mo Alloy
The isothermal oxidation behavior of Ti-24Al-14Nb-3V-0.5Mo alloy in synthetic air from 700°C to 1000°C was studied. The main emphasis was focused on the effect of microstructure obtained by different processes of melting and hot rolling, i.e. large and duplex of 2+B2, on the oxidation resistance. Regardless of the microstructure, the overall oxidation process of the specimens exposed at 700°C was dominantly controlled by the beneficial effect of Nb-addition due to the formation of a continuous -Al2O3 layer in the scale. However, both specimens showed poor oxidation resistance above 900°C, especially for the as-rolled specimen, because of higher volume fraction of the 2-phase. The spallation occurred in both specimens at 1000°C, which was probably relative to the formation of Ti2AlN between the thick scale and the substrate except for the TiO2 and -Al2O3.
In situ tensile deformation and fracture behavior of Ti–24Al–14Nb–3V–0.5Mo alloy with various microstructures
Abstract The tensile deformation and fracture behavior of Ti–24Al–14Nb–3V–0.5Mo alloy (at.%) with various microstructures were studied at room temperature and 700 °C by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). O-phase precipitates in the aged alloy contributed to the improvement of the ductility by dispersing operative dislocations and suppressing the planar slip in the α2+O grains. The primary α2 grain was strengthened owing to interruption of the movement of dislocations by fine O plates, resulting in a blocking of the crack nucleation and propagation during the tensile loading. In this case, the slip bands were concentrated in the α2+O phases, and the cracks nucleated at the α2/B2 boundaries and/or at the cleavage of the secondary α2 grains followed by propagation across the secondary acicular α2-phases. In the alloy with low volume fraction of the α2-phase, the deformation was concentrated in the B2-phase showing coarse slip bands, and the cracks nucleated and propagated along the cleavage planes of the B2-phase. When the volume fraction of the α2-phase was moderate, the cracks nucleated within the primary α2-phases and/or along the α2/B2 boundaries, and propagated along the α2/B2 boundaries and/or sheared across the α2 grains.
Simulation Analysis of Local Heat Treatment Formability of an Aerospace Aluminum Alloy Frame Parts
Wang Zhijian1,a, Guo Fangyu1,b, Shang Xiaofeng1,c, Song Hongwu2,d, Wang Ling3,e and Wang Jiale1,f 1School of Mechatronics Engineering, Shenyang Aerospace University, Shenyang 110136, China 2Institute of Metal Research, Chinese Academy of Science, Shenyang 110016, China 3Shenyang aircraft industry company, Shenyang 110134, China aWangzhijian1974@sina.com, b1486121506@qq.com, c1009074102@qq.com dhwsong@imr.ac.cn, ew_ling2008@aliyun.com, f1591897439@qq.com