The high-temperature plastic deformation behavior of BT25y alloy with an initial equiaxed microstructure was investigated by hot compression tests. Processing maps were established to evaluate the power dissipation ef...The high-temperature plastic deformation behavior of BT25y alloy with an initial equiaxed microstructure was investigated by hot compression tests. Processing maps were established to evaluate the power dissipation efficiency （η） and identify the flow instability regions. When the strain reaches steady state, the optimum processing window is distributed in the area covering most of the studied deformation temperatures and strain rates of 1 × 10-2 to 1× 10-1 s-1. True strain has great effects on the power dissipation efficiency under the condition of 880 ℃/1× 10-3 s-1, but the efficiency values remain approximately constant （η= 0.40） at conditions of 900-940 ℃/1× 10-2 to 1 × 10-1 S-1 and 980-1000 ℃/ 1× 10-1 s- 1. Besides, the instability regions are distributed in high strain rate areas no matter how many of the strains. Based on the processing map and microstructural observa- tion, it can be concluded that the deformation mechanisms related to Region I with small strain rate and lower temper- ature in α＋β phase field, Region II with medium strain rate and higher temperature inα＋β phase field, Region III with medium strain rate and high temperature in βphase field are superplasticity and strain-induced transformation, dynamicrecrystallization （DRX） and phase transformation, β phase dynamic recovery and local DRX, respectively.展开更多
对BT25Y合金电子束焊接样品进行700℃/2 h AC的退火处理和940℃/2 h AC+600℃/8 h AC的固溶+时效处理工艺,研究2种热处理工艺对合金焊接区域的组织和力学性能影响。结果表明,无热处理情况下,焊缝溶合区主要由α′马氏体构成,焊缝区硬度...对BT25Y合金电子束焊接样品进行700℃/2 h AC的退火处理和940℃/2 h AC+600℃/8 h AC的固溶+时效处理工艺,研究2种热处理工艺对合金焊接区域的组织和力学性能影响。结果表明,无热处理情况下,焊缝溶合区主要由α′马氏体构成,焊缝区硬度和强度明显高于基体。700℃/2 h AC退火处理后,焊缝区的α′马氏体转变为细小弥散的α相,焊缝区的硬度和强度高于基体,室温拉伸断裂发生在基体,焊接样品具有较差的高温持久性能。940℃/2 h AC+600℃/8 h AC的固溶+时效处理,焊缝熔合区的α′马氏体转变为尺寸较大的片层α相,并且沿原始凝固β晶界存在尺寸较大的连续或断续棒状α析出带,该析出带使得焊接样品在室温拉伸时沿焊缝发生脆性沿晶断裂,该热处理后合金具有较好的高温持久性能。展开更多
基金financially supported by the National Natural Science Foundation of China (No.51175431)
文摘The high-temperature plastic deformation behavior of BT25y alloy with an initial equiaxed microstructure was investigated by hot compression tests. Processing maps were established to evaluate the power dissipation efficiency （η） and identify the flow instability regions. When the strain reaches steady state, the optimum processing window is distributed in the area covering most of the studied deformation temperatures and strain rates of 1 × 10-2 to 1× 10-1 s-1. True strain has great effects on the power dissipation efficiency under the condition of 880 ℃/1× 10-3 s-1, but the efficiency values remain approximately constant （η= 0.40） at conditions of 900-940 ℃/1× 10-2 to 1 × 10-1 S-1 and 980-1000 ℃/ 1× 10-1 s- 1. Besides, the instability regions are distributed in high strain rate areas no matter how many of the strains. Based on the processing map and microstructural observa- tion, it can be concluded that the deformation mechanisms related to Region I with small strain rate and lower temper- ature in α＋β phase field, Region II with medium strain rate and higher temperature inα＋β phase field, Region III with medium strain rate and high temperature in βphase field are superplasticity and strain-induced transformation, dynamicrecrystallization （DRX） and phase transformation, β phase dynamic recovery and local DRX, respectively.
文摘对BT25Y合金电子束焊接样品进行700℃/2 h AC的退火处理和940℃/2 h AC+600℃/8 h AC的固溶+时效处理工艺,研究2种热处理工艺对合金焊接区域的组织和力学性能影响。结果表明,无热处理情况下,焊缝溶合区主要由α′马氏体构成,焊缝区硬度和强度明显高于基体。700℃/2 h AC退火处理后,焊缝区的α′马氏体转变为细小弥散的α相,焊缝区的硬度和强度高于基体,室温拉伸断裂发生在基体,焊接样品具有较差的高温持久性能。940℃/2 h AC+600℃/8 h AC的固溶+时效处理,焊缝熔合区的α′马氏体转变为尺寸较大的片层α相,并且沿原始凝固β晶界存在尺寸较大的连续或断续棒状α析出带,该析出带使得焊接样品在室温拉伸时沿焊缝发生脆性沿晶断裂,该热处理后合金具有较好的高温持久性能。
