F. Huang N.R. Tao K. Lu
材料科学技术（英文）
The microstructures and hardness of pure Al samples subjected to plastic deformation with different temperatures and strain rates were investigated. The results showed that the strain-induced grain refinement is significantly benefited by increasing strain rate and reducing deformation temperature. The saturated size of refined subgrains in Al can be as small as about 240 nm in cryogenic dynamic plastic deformation (DPD). Grain boundaries of the DPD Al samples are low-angle boundaries due to suppression of dynamic recovery during deformation. Agreement of the measured hardness with the empirical Hall-Petch relation extrapolated from the coarse-grained Al implies that the low-angle boundaries can contribute to strengthening as effective as the conventional grain boundaries.
关键词:
Dynamic plastic deformation
,
Microstructure
,
Hardness
,
Strain rate
,
Temperature
F. Huang N.R. Tao K. Lu
材料科学技术（英文）
The microstructures and hardness of pure Al samples subjected to plastic deformation with different temperatures and strain rates were investigated. The results showed that the strain-induced grain refinement is significantly benefited by increasing strain rate and reducing deformation temperature. The saturated size of refined subgrains in Al can be as small as about 240 nm in cryogenic dynamic plastic deformation (DPD). Grain boundaries of the DPD Al samples are low-angle boundaries due to suppression of dynamic recovery during deformation. Agreement of the measured hardness with the empirical Hall-Petch relation extrapolated from the coarse-grained Al implies that the low-angle boundaries can contribute to strengthening as effective as the conventional grain boundaries.
关键词:
Dynamic plastic deformation
,
Microstructure
,
Hardness
,
Strain rate
,
Temperature
Zhengyou TANG
,
Hua DING
,
Linxiu DU
,
Long LI
材料科学技术（英文）
Microstructure consisting of ferrite, bainite and retained austenite can be obtained through intercritical annealing and isothermal treatment in bainite transformation region for low silicon TRIP (transformation induced plasticity) steel containing niobium. Effects of strain rate, Nb content and soaking temperature in bainite region on microstructure and mechanical properties of test steels were investigated. It is shown that as strain rate ranges from 10-2 to 10-4 s-1, the volume fraction of transformed martensite from retained austenite, as well as tensile strength, elongation rate and strength-ductility product, increases. When Nb is added, the volume fraction of retained austenite decreases, but tensile strength and yield strength increase. While Nb content reaches 0.014%, the steel exhibits high elongation and combination of strength and ductility. Higher retained austenite volume fraction and good mechanical properties are obtained in the test steels when the soaking temperature in bainite region is 400oC. The maximum values of tensile strength, total elongation rate and strength-ductility product can reach 739 MPa, 38% and 28082 MPa%, respectively.
关键词:
TRIP
,
null
,
null
,
null
,
null
刘婵桢
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2015.05.010
基于热模拟机GLEEBLE1500,以AZ31为研究对象进行热压缩实验,获得材料的应力-应变曲线.用金相显微镜对不同温度及应变速率下的金相进行观察分析,并对比分析热压缩前后的微观组织.同时分析了不同温度及应变速率下材料的力学行为,其行为属于典型的动态再结晶型.当热压缩温度为350℃和400℃时,材料强度随应变速率增大而增大,且加工硬化也增大.当应变速率为0.01和0.1/s时,随着变形温度的升高,材料的应力逐渐降低.在不同温度下,应变速率为0.01/s时的应力比应变速率为0.1/s时的应力要低.
关键词:
AZ31
,
热变形行为
,
微观组织
,
应变速率
,
变形温度
