scholarly journals Simulation of Grain Refinement Induced by High-Speed Machining of OFHC Copper Using Cellular Automata Method

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Jun Zhang ◽  
Xiang Xu ◽  
José Outeiro ◽  
Hongguang Liu ◽  
Wanhua Zhao
Keyword(s):  
High Temperature ◽  
Cellular Automata ◽  
High Strain Rate ◽  
Strain Rate ◽  
Grain Refinement ◽  
High Speed ◽  
High Strain ◽  
Machining Process ◽  
Ofhc Copper ◽  
High Speed Machining

Abstract During high-speed machining (HSM), the microstructure of materials evolves with significant plastic deformation process under high strain rate and high temperature, which affects chip formation and material fracture mechanisms, as well as surface integrity. The development of models and simulation methods for grain refinement in machining process is of great importance. There are few models which are developed to predict the evolution of the grain refinement of HSM in mesoscale with sufficient accuracy. In this work, a cellular automata (CA) method with discontinuous (dDRX) and continuous (cDRX) dynamic recrystallization (DRX) mechanisms is applied to simulate the grain refinement and to predict the microstructure morphology during machining oxygen-free high-conductivity (OFHC) copper. The process of grain evolution is simulated with the initial conditions of strain, strain rate, and temperature obtained by finite element (FE) simulation. The evolution of dislocation density, grain deformation, grain refinement, and growth are also simulated. Moreover, cutting tests under high cutting speeds (from 750 m/min to 3000 m/min) are carried out and the microstructure of chips is observed by electron backscatter diffraction (EBSD). The results show a grain refinement during HSM, which could be due to the occurrence of dDRX and cDRX. High temperature will promote grain recovery and growth, while high strain rate will significantly cause a high density of dislocations and grain refinement. Therefore, HSM contributes to the fine equiaxed grain structure in deformed chips and the grain morphology after HSM can be simulated successfully by the CA model developed in this work.

scholarly journals Thermomechanical tensile properties of deposited Inconel 718 superalloy over a wide range of strain rate and temperature

2021 ◽  
Vol 250 ◽  
pp. 05017
Author(s):  
Martina Scapin ◽  
Lorenzo Peroni ◽  
Kangbo Yuan ◽  
Weiguo Guo
Keyword(s):  
High Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Speed ◽  
High Strain ◽  
Heating System ◽  
Tensile Tests ◽  
Significant Drop ◽  
Nominal Strain Rate ◽  
Wide Range

Nickel-based superalloys show high strength retained also at high temperature and they are widespread used for structural components exposed during services to high temperature combined with high strain rate or impact loading conditions. The objective of this study was the investigation of the plastic flow behaviour of Laser Metal Deposited Nickel-based superalloy Inconel718. The material was manufactured at Northwestern Polytechnical University in China. Specimens with three different heat treatment conditions were investigated: as-deposited, directly aged and aged after homogenization and solution. High strain rate tensile tests were performed on the direct Hopkinson bar setup developed at DYNLab laboratory at Politecnico di Torino. At a nominal strain rate of 1500 s-1 the temperature sensitivity was investigated between 20 and 1000°C. An induction heating system was adopted, and the temperature was monitored by thermocouples and infrared pyrometer and high-speed camera. The results showed the materials strength decreases as a function of temperature with a significant drop starting from 800 °C. An asymmetric tension-compression behaviour was found by comparing the results with data in compression. The strain rate influence was investigated at room temperature and very limited or negligible sensitivity was found covering six orders of magnitude in strain rate.

The Effect of Strain Rate on the Material Characteristics of Nickel-Based Superalloy Inconel 718

2007 ◽  
Vol 340-341 ◽  
pp. 283-288 ◽  
Author(s):  
Jung Han Song ◽  
Hoon Huh
Keyword(s):  
Dynamic Response ◽  
High Strain Rate ◽  
Strain Rate ◽  
Turbine Blade ◽  
Inconel 718 ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Experimental Results ◽  
Stress Wave Propagation

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic material properties of the Inconel 718 alloy which is widely used in the high speed turbine blade. The dynamic response at the corresponding level of the strain rate should be acquired with an adequate experimental technique and apparatus due to the inertia effect and the stress wave propagation. In this paper, the dynamic response of the Inconel 718 at the intermediate strain rate ranged from 1/s to 400/s is obtained from the high speed tensile test and that at the high strain rate above 1000/s is obtained from the split Hopkinson pressure bar test. The effects of the strain rate on the dynamic flow stress, the strain rate sensitivity and the failure elongation are evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 3000/s are interpolated in order to construct the constitutive relation that should be applied to simulate the dynamic behavior of the turbine blade made of the Inconel 718.

Viscoplastic Constitutive Model for High Strain Rate Mechanical Properties of SAC-Q Leadfree Solder After High-Temperature Prolonged Storage

2018 ◽  
Author(s):  
Pradeep Lall ◽  
Vikas Yadav ◽  
Jeff Suhling ◽  
David Locker
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
Thermal Aging ◽  
High Strain ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Aging Effects ◽  
Model Predictions

Electronics in automotive underhood and downhole drilling applications may be subjected to sustained operation at high temperature in addition to high strain-rate loads. SAC solders used for second level interconnects have been shown to experience degradation in high strain-rate mechanical properties under sustained exposure to high temperatures. Industry search for solutions for resisting the high-temperature degradation of SAC solders has focused on the addition of dopants to the alloy. In this study, a doped SAC solder called SAC-Q solder have been studied. The high strain rate mechanical properties of SAC-Q solder have been studied under elevated temperatures up to 200°C. Samples with thermal aging at 50°C for up to 6-months have been used for measurements in uniaxial tensile tests. Measurements for SAC-Q have been compared to SAC105 and SAC305 for identical test conditions and sample geometry. Data from the SAC-Q measurements has been fit to the Anand Viscoplasticity model. In order to assess the predictive power of the model, the computed Anand parameters have been used to simulate the uniaxial tensile test and the model predictions compared with experimental data. Model predictions show good correlation with experimental measurements. The presented approach extends the Anand Model to include thermal aging effects.

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