摘要
采用连续变断面循环挤压对TC4钛合金进行变形,研究变形工艺参数对TC4合金沿径向显微组织及显微硬度的影响。结果表明,随着变形温度升高,α相尺寸虽然变化较小但还是有一定程度的长大;变形速度对显微组织中初生α相的含量影响较小,但对其形态和晶粒尺寸的影响相对较大:低速变形时,初生α相呈长条状,而以较高速度变形时,初生α相晶粒呈等轴状,且晶粒有一定程度细化,这是由于在该变形条件下发生了完全动态再结晶;随着变形道次的增加,晶粒细化程度增加,当试样经6道次循环挤压后组织细化效果显著,由原始尺寸的10μm细化至4μm。变形温度及变形速度对试样沿径向的显微硬度分布影响较小,但循环道次却对其影响较显著,随着循环道次的增加,试样沿径向显微硬度值较高且同一试样上的差异较小、分布较均匀,这与组织得到显著细化及均匀化有关。
The TC4 titanium alloy was deformed by continuous variable cross-section recycled extrusion, and the effects of deformation processing parameters on the microstructure and the micro hardness along the radial of the specimen have been investigated. The results show that the change of the grain size of the a phase is small with the increase of deformation speed or temperature, but its size becomes coarse to a certain extent with increasing of deformation temperature. The deformation speed has little effect on the volume fraction of the primary a phase, but it has relatively significant effect on its shape and size. The primary a phase grain is elongated while the specimen is deformed at lower speed. However, the primary a phase grain is refined to a certain extent and shows the equiaxed while the specimen is deformed at higher speed, which is attributed to the sufficient proceeding of dynamic recrystallization in the deformation. The refined degree of the grains is enhanced with increasing of deformation loop. When the specimen is undergone 6 loops extrusion, the size of the a phase is reduced from 10 to 4 μm. In addition, the deformation temperature and deformation speed have little effect on the micro hardness distribution along the radial of the specimen, but the loop has a very significant effect on it. As the loop increases, the micro hardness value is higher and their differences are little along the radial in the same specimen, the reason is that the microstructure is refined and homogenized significantly
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2014年第2期440-444,共5页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51101116)
关键词
TC4钛合金
连续变断面循环挤压
变形工艺参数
显微组织
显微硬度
TC4 titanium alloy
continuous variable cross-section recycled extrusion
deformation processing parameter
microstructure
micro hardness
