Thermomechanical response of a powder metallurgy Ti−6Al−4V alloy modified with 2.9 Pct Boron
Thermomechanical response of a powder metallurgy Ti−6Al−4V alloy modified with 2.9 Pct Boron
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DOI：
10.1007/s11661-005-1014-2
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发表时间：
2005-03
期刊：
影响因子：
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通讯作者：
R. Bhat;S. Tamirisakandala;D. Miracle;V. Ravi
中科院分区：
文献类型：
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作者：
R. Bhat;S. Tamirisakandala;D. Miracle;V. Ravi
通过等温恒应变速率热压缩试验，研究了混合粉末冶金法制备的2.9%B改性的Ti−6Al−4V合金在85 0℃~12 0 0℃、10−3~10s−1应变速率范围内的热机械响应。在α+β相场中，在低应变率(<；10−1s−1)下，基体/TiB界面处发生空化和TiB颗粒断裂，而在高应变率下也发生绝热剪切带化。在低应变速率下，由于TiB颗粒稳定了细晶尺寸，β相发生超塑性变形。观察到晶界和基体/TiB界面的滑动与同时的扩散调节对β超塑性的贡献。β相场中的高应变速率变形行为与α+β相场中的变形行为相似，表现为基体/TiB相界面处的大量空化和TiB颗粒的断裂。
The thermomechanical response of Ti−6A1−4V modified with 2.9 pct B produced by a blended powder metallurgy route was studied with isothermal constant strain-rate hot compression tests in the temperature range 850°C to 1200°C and strain rate range 10−3to 10s−1. Detailed analyses of the flow stress data were conducted to identify various microstructural deformation and damage mechanisms during hot working by applying available materials modeling techniques. In the α+β phase field, cavitation at the matrix/TiB interfaces and TiB particle fracture occurs at low strain rates (<10−1s−1), while adiabatic shear banding also occurs at high strain rates. At low strain rates, the β phase deforms superplastically due to the stabilization of a fine grain size by the TiB particles. Grain boundary and matrix/TiB interface sliding with simultaneous diffusional accommodation are observed to contribute to the β superplasticity. The deformation behavior at high strain rates in the β-phase field is similar to that of the α+β phase field, with microstructural manifestations of extensive cavitation at the matrix/TiB interfaces and TiB particle fracture.