Modelling Recovery and Recrystallisation Kinetics after Intercritical Deformation in 0.19 wt% C 1.5 wt% Mn Steel

2004 ◽  
Vol 467-470 ◽  
pp. 329-334 ◽  
Author(s):  
A. Smith ◽  
A. Miroux ◽  
Haiwen Luo ◽  
Jilt Sietsma ◽  
Sybrand van der Zwaag

The softening kinetics of a 0.19 wt% C 1.5 wt% Mn steel deformed at two intercritical temperatures have been characterised using the stress relaxation technique. Recrystallisation of intercritical austenite has been modelled using a single grain model (Chen et al., 2002 [1]), whilst recovery of both intercritical austenite and ferrite has been modelled using a model in the literature [Verdier et al., 1999 [2]). The models are combined to predict the overall softening kinetics with a rule of mixtures formulation. Comparison of the model with experiment shows significant deviations. The reasons are discussed with reference to the mixture rule and to the local stress-strain distribution which exists in the deformed samples. A simple modification to the model is proposed which takes into account the effect of a local stress distribution in deformed austenite.

2004 ◽  
Vol 467-470 ◽  
pp. 293-298 ◽  
Author(s):  
Haiwen Luo ◽  
Jilt Sietsma ◽  
Sybrand van der Zwaag

The austenite recrystallization kinetics in the intercritical region of a C-Mn steel is investigated by means of stress relaxation tests. It is found that the Avrami exponent, n, decreases significantly with decreasing temperature, i.e. with increasing ferrite fraction. This behaviour deviates from that of austenite recrystallization in the purely austenitic state, in which case the Avrami exponent is constant and independent of temperature and deformation. To interpret this, the influence of spatial variation of the plastic strain in the intercritical austenite grains on recrystallization kinetics is modelled quantitatively. The modelling results seem to indicate that the strain heterogeneity is responsible for the decreasing Avrami exponent with decreasing intercritical temperature.


2014 ◽  
Vol 40 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Marzieh Alikhasi ◽  
Hakimeh Siadat ◽  
Allahyar Geramy ◽  
Ahmad Hassan-Ahangari

The purpose of this study was to evaluate the influence of the stress/strain distribution in buccal bone of an anterior maxillary implant using 3 bone thicknesses under 5 different loading angles. Different testing conditions incorporating 3 buccal bone thicknesses, 3 bone compositions, and 5 loading angles of an anterior maxillary implant were applied in order to investigate the resultant stress/strain distribution with finite element analysis. The maximum equivalent stress/strain increased with the decreasing of loading angle relative to the long axis. In addition to loading angle, bone quality and quantity also influenced resultant stress distribution. Dental practitioners should consider combinations of bone composition, diameter, and load angulations to predict success or failure for a given implant length and diameter.


2011 ◽  
Vol 1282 ◽  
Author(s):  
Yukako Kato ◽  
Hitoshi Umezawa ◽  
Tokuyuki Teraji ◽  
Shin-ichi Shikata

ABSTRACTSemiconductor epitaxial CVD single crystal diamond is considered a potential material for power devices because of its unique characteristics. In the discussion on the relationship between crystal quality and device performance, the atomic purity and defect concentration have been considered; however, the information on the local stress-strain distribution in a single crystal is not sufficient. In this paper, the local stress-strain distribution of the epitaxial CVD single crystal diamond is quantitatively examined using the birefringence and cathodoluminescence images and the Raman peak-shift map. From the Raman peak-shift map, the local stress-strain is estimated and the stress is found to range from -67 MPa to +160 MPa in the observed area.


2006 ◽  
Vol 77 (8) ◽  
pp. 595-602 ◽  
Author(s):  
Ali Smith ◽  
Alexis Miroux ◽  
Jilt Sietsma ◽  
Sybrand van der Zwaag

2019 ◽  
Vol 85 (2) ◽  
pp. 42-47
Author(s):  
A. A. Bautin ◽  
Yu. A. Svirsky ◽  
A. V. Pankov

The paper describes one of the most promising ways of structure health monitoring based on analysis of the kinetics of local stress-strain state. Comparison with other methods of damage detection and advantages of the stress-strain state control are considered. To implement this method of monitoring, two types of sensors are considered: strain gauges and fiber Bragg gratings (FBG). The advantages of FBG, due to which their use in operation is most preferable, are presented. The possibility of using stress-strain state control is analyzed for a promising transport aircraft using the results of tensometry under cyclic loading. The relevance of the work is confirmed by various examples of using monitoring methods in on-board systems during operation. The possibility of monitoring the airframe parts is demonstrated for longitudinal fuselage joints as an example. The change in the stress-strain state of the longitudinal joints, caused by structural damage was confirmed by tensometry analysis and by analysis of the stress-strain state of bearing sheet by the finite element method (FEM), taking into account the fatigue cracks originated during cyclic loading. The results of the calculation are compared with the tensometry data. Proceeding from the results of the calculation of the stress-strain state of the damaged and undamaged structure, the zones of the greatest deformation change are determined to optimize potential locations for the sensors. The optimal placing of the sensors for monitoring the integrity of the joints is proposed. The study confirms that the method of damage monitoring of the structure, developed on the basis of changes in the kinetics of the stress-strain state, can be successfully used in tests for maintaining the integrity of joints and other places with multi-site damages, where the methods of visual and non-destructive testing are not effective.


2006 ◽  
Vol 77 (8) ◽  
pp. 603-613 ◽  
Author(s):  
Ali Smith ◽  
Alexis Miroux ◽  
Jilt Sietsma ◽  
Sybrand van der Zwaag

Author(s):  
Xiaoling He ◽  
Clemens Burda

Stress voiding is a common defect of the semiconductor interconnect. In thermal cycles, other defects such as the hillocks, delamination can also occur. For the Cu/low-k interconnect, simulation with Ansys is made to analysis the interconnect stress-strain distribution and deformation. Results indicate that stress induced void is prone to form in the via than in the metal lines. Flower defect appear at the via top can also be analyzed based on the stress distribution. It is found that Von-Mises stress represent the localization of the stress concentration, which cause delamination and over-stress failure at the interface of the different materials.


2021 ◽  
pp. 116828
Author(s):  
Akinobu Shibata ◽  
Takashi Yonemura ◽  
Yuji Momotani ◽  
Myeong-heom Park ◽  
Shusaku Takagi ◽  
...  

2018 ◽  
Vol 941 ◽  
pp. 633-638
Author(s):  
John Joseph Jonas ◽  
Clodualdo Aranas Jr. ◽  
Samuel F. Rodrigues

Under loading above the Ae3 temperature, austenite transforms displacively into Widmanstätten ferrite. Here the driving force for transformation is the net softening during the phase change while the obstacle consists of the free energy difference between austenite and ferrite as well as the work of shear accommodation and dilatation during the transformation. Once the driving force is higher than the obstacle, phase transformation occurs. This phenomenon was explored here by means of the optical and electron microscopy of a C-Mn steel deformed above their transformation temperatures. Strain-temperature-transformation (STT) curves are presented that accurately quantify the amount of dynamically formed ferrite; the kinetics of retransformation are also specified in the form of appropriate TTRT diagrams. This technique can be used to improve the models for transformation on accelerated cooling in strip and plate rolling.


ACS Omega ◽  
2021 ◽  
Author(s):  
Takahiro Doi ◽  
Hideaki Takagi ◽  
Nobutaka Shimizu ◽  
Noriyuki Igarashi ◽  
Shinichi Sakurai

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