scholarly journals Effects of Helium and Displacement Damage on Microstructural Evolution in Helium-Implanted Martensitic Steel HCM12A Examined by TEM and Positron Annihilation Lifetime Measurement

2020 ◽  
Author(s):  
Eiichi Wakai ◽  
Shuhei Nogami ◽  
Akira Hasegawa ◽  
Tetsuya Hirade ◽  
Shigeru Takaya ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Microstructural Evolution ◽  
Martensitic Steel ◽  
Lifetime Measurement ◽  
Displacement Damage ◽  
Positron Annihilation Lifetime

Effects of Helium Production and Displacement Damage on Microstructural Evolution and Mechanical Properties in Helium-Implanted Austenitic Stainless Steel and Ferritic/Martensitic Steel

2021 ◽  
Vol 1024 ◽  
pp. 53-69
Author(s):  
Eiichi Wakai ◽  
Shuhei Nogami ◽  
Akira Hasegawa ◽  
Nariaki Okubo ◽  
Shigeru Takaya ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Microstructural Evolution ◽  
Martensitic Steel ◽  
Microstructural Development ◽  
Displacement Damage ◽  
Lifetime Measurements ◽  
Helium Concentration ◽  
Positron Annihilation Lifetime

The effects of helium concentration and displacement damage on microstructural evolution at low dpa and low helium concentration were mainly investigated in specimens of austenitic stainless steel 316FR or SUS304 and a high chromium martensitic steel (HCM12A). The 316FR and HCM12A specimens were implanted uniformly with helium at 823 K up to 30 appm-He or 50 appm-He by 50 MeV cyclotron accelerator using energy degraders. After the helium implantation, the microstructures were examined by a transmission electron microscopy and positron annihilation lifetime measurements. Irradiation hardening behaviors were analyzed using SUS304 and HCM12A steels at 823 K implanted with He ion up to 100 appm with different He/dpa ratios in the HIT ion irradiation experiments and the hardening behaviors were examined by nano indentation method. In the irradiation and annealing specimens, these mechanical properties and microstructures were examined to understand the effects of helium production, displacement damage and annealing on microstructural development, and kinetic Monte Carlo (kMC) simulations were also performed to understand the microstructural development, and the results were compared with the results of TEM observation and positron annihilation lifetime measurements. Important some differences in the microstructural developments such as cavity formation and growth between austenitic stainless steel and martensitic steel were observed in low dpa and low helium concentration conditions.

Analysis of Creep Deformation Process of Heat Resistant Steels Using Positron Annihilation Lifetime

2007 ◽  
Vol 561-565 ◽  
pp. 2233-2236 ◽  
Author(s):  
Masaaki Igarashi ◽  
Koji Moriguchi ◽  
Seiichi Muneki ◽  
Fujio Abe ◽  
Yasuharu Shirai
Keyword(s):  
Creep Rate ◽  
Positron Annihilation ◽  
Microstructural Evolution ◽  
Creep Deformation ◽  
Deformation Mechanism ◽  
Deformation Process ◽  
Creep Damage ◽  
Lifetime Measurement ◽  
Positron Annihilation Lifetime ◽  
Heat Resistant Steels

Creep deformation mechanism of the steels with a different matrix, α (ferrite), α’ (martensite) and γ (austenite), and precipitates such as MX and M23C6 has been analyzed using positron annihilation lifetime measurement. The positron annihilation lifetime has been found to be a very useful tool for evaluating the characteristic creep damage of the steels with different microstructure and the corresponding microstructural evolution during creep deformation. The creep deformation process of the α steel is heterogeneous, while the α’+M23C6 steel exhibits gradual changes in the creep rate in both transient and acceleration creep regions with the largest off-set strain, implying the homogeneous creep deformation. The α’+M23C6+ MX steel is in between the α and α’+M23C6 steels. The homogeneous creep deformation takes place in the γ steel.

Positron annihilation lifetime measurement and X-ray analysis on 120 MeV Au +7 irradiated polycrystalline tungsten

2015 ◽  
Vol 467 ◽  
pp. 406-412 ◽  
Author(s):  
Charu Lata Dube ◽  
Pawan Kumar Kulriya ◽  
Dhanadeep Dutta ◽  
Pradeep K. Pujari ◽  
Yashashri Patil ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Lifetime Measurement ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Polycrystalline Tungsten

Positron Annihilation Lifetime Measurement in Supercritical Fluid of N2O

2004 ◽  
Vol 445-446 ◽  
pp. 295-297
Author(s):  
Kazushi Funakoshi ◽  
Yasushi Kino ◽  
Tsutomu Sekine ◽  
Hiroshi Kudo ◽  
Yasuo Ito ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Supercritical Fluid ◽  
Lifetime Measurement ◽  
Positron Annihilation Lifetime
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