摘要
采用近等温锻造开坯工艺实验定量研究了增大变形量对Ti-46.5Al-2.5V-1.0Cr-0.3Ni合金变形组织均匀性和力学性能稳定性的作用。通过锻坯组织观察分析及硬度、强度分布测试,揭示了TiAl合金近等温锻造过程中变形量与宏观组织和微观组织均匀性的基本关系。结果表明:近等温锻造变形量为65%,70%,75%,80%,85%时,随着变形量的增大,TiAl合金锻坯内的宏观变形流线分布趋于均匀,均匀变形区域面积不断增大,变形量85%时均匀变形区面积增加至68.0%,微观变形组织由等轴的γ和α2,以及很少量的残余层片团组成,晶粒尺寸明显细化,且等轴组织在合金中占到了绝大部分;锻坯硬度分布测试表明随着近等温锻造变形量的增大,均匀变形区域的硬度变化基本趋于均匀一致,且硬度平均值也在不断增高;锻坯难变形区和均匀变形区经1250℃/15h/AC热处理后取样进行室温压缩测试,随着近等温锻造变形量的增加锻坯各部位室温压缩应力应变数据分散度降低,性能稳定性提高。
The effects of increasing deformation strain on the microstructure uniformity and mechanical property stability of Ti-46.5Al-2.5V-1.0Cr-0.3Ni alloy were quantitative studied by single near-iso thermal forging. The observed microstructure and measured hardness and strength can revealing the basic relationship among deformation strain, macrostructure and microstructure. The results show that distribution of flow lines is more uniform and the area of uniform zone is enlarged with the engineering strain raised from 65%, 70%, 75%, 80% to 85%. In the forged pancake, the proportion of uniform zone expand to 68.0% when the strain is 85%. And the deformation microstructure is composed by equiaxed γ,α2 and a few remnant laminas. The grain dimension is obviously refined and the vast majority is equiaxial microstructure. The hardness testing shows that hardness of uniform zone is tending to be uniformity and the average hardness is continuous to increase. The room temperature compression samples were machined from stagnant zone and uniform zone with heat treatment at 1250℃/15h/AC. The dispersity of room temperature compression results is reduced and it means that property stability is improved with the increased engineering strain.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2013年第6期40-44,共5页
Journal of Materials Engineering
基金
中南林业科技大学青年科学研究基金重点项目(QJ2010001A)
关键词
TIAL合金
大变形量
近等温锻造
组织性能
TiAl alloy
large deformation
near-isothermal forging
microstructure and property
