OS6(4)-18(OS06W0141) Analysis of Crack Propagation Behavior in Nano Size hcp Crystals by Molecular Dynamic Method

2003 ◽  
Vol 2003 (0) ◽  
pp. 233
Author(s):  
Shinji Ando ◽  
Katsuhiro Oyabu ◽  
Kousei Hirayama ◽  
Masayuki Tsushida ◽  
Hideki Tonda
Keyword(s):  
Crack Propagation ◽  
Molecular Dynamic ◽  
Molecular Dynamic Method ◽  
Dynamic Method ◽  
Propagation Behavior ◽  
Nano Size ◽  
Crack Propagation Behavior

Molecular Dynamic Simulation of Crack Propagation Behavior in Nano Size HCP Crystals

2005 ◽  
Author(s):  
Shinji Ando ◽  
Leping Bu ◽  
Masayuki Tsushida ◽  
Hideki Tonda
Keyword(s):  
Crack Propagation ◽  
Initial Crack ◽  
Prismatic Slip ◽  
Crack Plane ◽  
Propagation Behavior ◽  
Model Crystal ◽  
Nano Size ◽  
Crack Propagation Behavior ◽  
Dynamics Method ◽  
Type Potential

A crack propagation behavior of nano size hcp crystal (13nm × 24nm × 4.6nm) has been simulated by molecular dynamics method using Lennard-Jones type potential. In a case of model crystal with initial notch plane and direction were (1010), [1210], the crack propagated parallel to notch plane and two sets of prismatic slips were occurred at the crack. Therefore, the crack in this crystal is deduced to extend by alternating shear on two intersecting {1010}<1210> prismatic slip systems. In a model crystal with (0001), [1010] initial crack, {1011} first order pyramidal slip occurred at crack tip and following {1012} twin was also observed. In the model crystal with (1010)[0001] initial crack, the crack propagated parallel to initial crack plane with two prismatic slips in front of the crack. To understand strength of nano size titanium crystals as MEMS materials, stress intensity factor, K of each model crystals were also estimated from stress-strain curves obtained from these simulations.

scholarly journals Crack Propagation Behavior of a Ni-Based Single-Crystal Superalloy during In Situ SEM Tensile Test at 1000 °C

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1047
Author(s):  
Wenxiang Jiang ◽  
Xiaoyi Ren ◽  
Jinghao Zhao ◽  
Jianli Zhou ◽  
Jinyao Ma ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Tensile Test ◽  
Single Crystal ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Single Crystal Superalloy ◽  
Propagation Path ◽  
Propagation Behavior ◽  
Crack Propagation Behavior

An in situ scanning electron microscope (SEM) tensile test for Ni-based single-crystal superalloy was carried out at 1000 °C. The stress displacement was obtained, and the yield strength and tensile strength of the superalloy were 699 MPa and 826 MPa, respectively. The crack propagation process, consisting of Model I crack and crystallographic shearing crack, was determined. More interestingly, the crack propagation path and rate affected by eutectics was directly observed and counted. Results show that the coalescence of the primary crack and second microcrack at the interface of a γ/γ′ matrix and eutectics would make the crack propagation rate increase from 0.3 μm/s to 0.4 μm/s. On the other hand, crack deflection decreased the rate to 0.05 μm/s. Moreover, movement of dislocations in front of the crack was also analyzed to explain the different crack propagation behavior in the superalloy.

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