Investigation of Deformation Gradients in Surface Zone of Mechanically Surface Treated CuZn30

2007 ◽  
Vol 561-565 ◽  
pp. 2229-2232 ◽  
Author(s):  
Sang Bong Yi ◽  
Tomasz Ludian ◽  
Lothar Wagner
Keyword(s):  
Plastic Deformation ◽  
Shot Peening ◽  
Cold Work ◽  
Local Deformation ◽  
Surface Zone ◽  
Ball Burnishing ◽  
Deformation Degree ◽  
Near Surface ◽  
Ball Size ◽  
Almen Intensity

The deformation degrees in near-surface zones and related microstructural changes in CuZn30 were determined after shot peening and ball-burnishing. The induced depths of plastic deformation increase with Almen intensity and rolling pressure in shot peening and ball-burnishing, respectively. As the ball size in burnishing increases, the depth of plastic deformation also increases. The local degrees of cold work within the affected depths were estimated by comparing micro-hardness values, penetration depths of induced slip bands as well as X-ray diffraction peak widths with those measured in blanks cold rolled to fixed degrees of plastic strain. The results clearly indicate that very high local deformation degrees above 80% are typically induced by mechanical surface treatments in areas very close to the surface with this deformation degree gradually decreasing with increasing distance to the surface. Depending on the intensity of ball-burnishing, deformation degrees still of the order of 10% were observed in regions having distances to the surface of as large as 1000 (m.

Effect of Optimization of Shot Peening Parameters on Surface Integrity of NAK80

2010 ◽  
Vol 426-427 ◽  
pp. 537-539 ◽  
Author(s):  
Hong Miao ◽  
Dun Wen Zuo ◽  
Hong Feng Wang ◽  
X.W. Sha
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Dislocation Density ◽  
Crack Initiation ◽  
Yield Stress ◽  
Surface Integrity ◽  
Shot Peening ◽  
Experimental Result ◽  
Near Surface ◽  
Crystal Block

Shot peening is known to improve the fatigue performance of materials. The improvement in fatigue is that plastic deformation in the surface increases hardness, yield stress and microstrain of thinning Crystal block and dislocation density, and formed advantaged compress residual stress that are introduced into the near-surface of the components and which hinder crack initiation and growth. But over peening effect is produced when shot peening strengthening goes beyond a certain limit, which was adverse to improve surface quality. This paper adopted the optimization of the critical peening parameters to avoid appearing over peening effect. The experimental result showed that arc high value of optimal shot peening was 0.40mm.

Bondability of Dissimilar Metal Sheets by Shot Peening

2013 ◽  
Vol 773-774 ◽  
pp. 818-823 ◽  
Author(s):  
Yasunori Harada ◽  
Masayuki Nunobiki
Keyword(s):  
Plastic Deformation ◽  
Shot Peening ◽  
Cast Steel ◽  
Pure Copper ◽  
The Other ◽  
Pure Aluminium ◽  
Low Carbon ◽  
Near Surface ◽  
Dissimilar Metal ◽  
Metal Sheets

In shot peening, bombarding the surface with steel shot propelled at high velocity causes plastic deformation of surface. The process with the characteristic deformation was applied to joining process. Our approach has been applied to the butt joining of the dissimilar metal sheets. In this method, however, the joint strength was lower than the flow stress of base metal. The modified joining processing was being carried out to improve the bondability. In the present study, the joining of dissimilar metal sheets using a shot peening process was investigated to improve the bondability. In the joined section, the edge of the joint area of the sheets were slit using a laser. In this method, the edges of the sheet are overlapped the other sheet. When the connection is peened, the material undergoes large plastic deformation near the surface due to the collision of shots. In this process, particularly noteworthy is the plastic flow near surface layer. The edges of the sheet are joined to the other sheet, thus two sheets can be joined each other. In the experiment, the shot peening treatment was performed by using an air-type peening machine. The shots used were made of high carbon cast steel. Air pressure was 0.6 MPa and peening time was in the range of 30-240s. The metal sheets were commercial low-carbon steel, stainless steel, pure aluminium, aluminium alloy, and pure copper. The effects of processing conditions on the bondability were mainly examined. It was found that the present method was effective for joining of dissimilar metal sheets.

Texture Gradients in Shot Peened Ti-2.5Cu

2010 ◽  
Vol 160 ◽  
pp. 141-146 ◽  
Author(s):  
Emad Maawad ◽  
Heinz Günter Brokmeier ◽  
Lothar Wagner
Keyword(s):  
Shot Peening ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
X Rays ◽  
Near Surface ◽  
Deep Impact ◽  
Solution Treated ◽  
Texture Characteristics ◽  
Almen Intensity ◽  
Mechanical Surface

Shot peening is a mechanical surface treatment having a deep impact on the materials which generates beneficial near-surface plastic deformation resulting in changes in peening texture characteristics. The present study aims to investigate the texture gradients in the solution treated (SHT) Ti-2.5Cu after shot peening with Almen intensity of 0.20 mmA. Due to a high transmission and a large beam cross-section of neutrons, texture analysis by neutron diffraction has become the standard method to investigate bulk textures. In contrary, the penetration depth of conventional X-rays is a relatively smaller than that of neutrons. Therefore, it is able to measure texture gradients in some hundred microns from the surface.

On effect of surface hardening on impact and abrasive wear resistance of Hadfi eld steel

2020 ◽  
pp. 252-255
Author(s):  
V.I. Bolobov ◽  
V.S. Bochkov ◽  
E.V. Akhmerov ◽  
V.A. Plashchinsky ◽  
E.A. Krivokrisenko E.A.
Keyword(s):  
Plastic Deformation ◽  
Wear Resistance ◽  
Abrasive Wear ◽  
Work Hardening ◽  
Surface Hardening ◽  
Cold Work ◽  
Abrasive Wear Resistance ◽  
Hadfield Steel ◽  
Mining Equipment ◽  
Effect Of Surface

On the example of Hadfield steel, as the most common material of fast-wearing parts of mining equipment, the effect of surface hardening by plastic deformation on their impact and abrasive wear resistance is considered. Wear test is conducted on magnetic ironstone as typical representative of abrasive and hard rock. As result of wear of initial samples with hardness of ∼200 HB and samples pre-hardened with different intensities to the hardness of 300, 337 and 368 HB, it is found that during the initial testing period, the initial samples pass the “self-cold-work hardening” stage with increase in hardness to ∼250 HB, which remains virtually unchanged during further tests; the hardness of the pre-hardened samples does not change significantly throughout the tests. It is established that the rate of impact-abrasive wear of pre-hardened samples is significantly (up to 1.4 times) lower than the original ones that are not subjected to plastic deformation, and decreases with increasing degree of cold-work hardening. Preliminary surface hardening by plastic deformation can serve as effective way to increase the service life of fast-wearing working parts of mining equipment.

DISPERSION IN SEISMIC SURFACE WAVES

Geophysics ◽  
1951 ◽  
Vol 16 (1) ◽  
pp. 63-80 ◽  
Author(s):  
Milton B. Dobrin
Keyword(s):  
Surface Waves ◽  
Water Waves ◽  
Seismic Refraction ◽  
Wave Theory ◽  
Wave Dispersion ◽  
Surface Zone ◽  
Surface Wave Dispersion ◽  
Near Surface ◽  
Arrival Times ◽  
Ground Roll

A non‐mathematical summary is presented of the published theories and observations on dispersion, i.e., variation of velocity with frequency, in surface waves from earthquakes and in waterborne waves from shallow‐water explosions. Two further instances are cited in which dispersion theory has been used in analyzing seismic data. In the seismic refraction survey of Bikini Atoll, information on the first 400 feet of sediments below the lagoon bottom could not be obtained from ground wave first arrival times because shot‐detector distances were too great. Dispersion in the water waves, however, gave data on speed variations in the bottom sediments which made possible inferences on the recent geological history of the atoll. Recent systematic observations on ground roll from explosions in shot holes have shown dispersion in the surface waves which is similar in many ways to that observed in Rayleigh waves from distant earthquakes. Classical wave theory attributes Rayleigh wave dispersion to the modification of the waves by a surface layer. In the case of earthquakes, this layer is the earth’s crust. In the case of waves from shot‐holes, it is the low‐speed weathered zone. A comparison of observed ground roll dispersion with theory shows qualitative agreement, but it brings out discrepancies attributable to the fact that neither the theory for liquids nor for conventional solids applies exactly to unconsolidated near‐surface rocks. Additional experimental and theoretical study of this type of surface wave dispersion may provide useful information on the properties of the surface zone and add to our knowledge of the mechanism by which ground roll is generated in seismic shooting.

scholarly journals Prediction of Residual Stress Relaxation of Shot Peened 2024-T351 Aluminum Alloy: Part 1

2011 ◽  
Vol 462-463 ◽  
pp. 1355-1360
Author(s):  
Omar Suliman Zaroog ◽  
Aidy Ali ◽  
Sahari B. Barkawi
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Applied Load ◽  
Cold Work ◽  
Cyclic Tests ◽  
Initial State ◽  
Loading Cycle ◽  
Residual Stress Relaxation ◽  
Alloy Part

It is important to account for residual stress relaxation phenomenon in the design of the component. Specimens of 2024-T351 aluminium alloy were used in this study. The specimens were shot peened under three different shot peening intensities. Cyclic tests for two load magnitudes were performed for 1, 2, 10, 1000 and 10000 cycles. Residual stresses, microhardness and the cold work percentage were measured at initial state and after each loading cycle for the three shot peening intensities and for the two loads. The study revealed that most of the drop in the residual stress, microhardness and cold work happened in the first cycle are dependent on the applied load.

Order-disorder phenomena in α -brass - III. Influence of plastic deformation

1960 ◽  
Vol 257 (1290) ◽  
pp. 363-385 ◽  
Keyword(s):  
Plastic Deformation ◽  
Cold Work ◽  
Stored Energy ◽  
High Concentration ◽  
Complex Behaviour ◽  
Second Stage ◽  
Third Stage ◽  
Anneal Hardening ◽  
Two Stages ◽  
Degree Of Order

The evolution of stored energy during heating for specimens of deformed α-brass is quite different from that previously observed for pure metals; the stored energy is much larger and at least three stages of evolution exist. These have been studied for deformation in torsion and tension and the results correlated with measurements of electrical resistivity, density and hardness. The large release of energy in the first two stages is attributed mainly to the return of order destroyed by plastic deformation; the degree of disorder after heavy cold work is much greater than after quenching (part II). However, slight deformation (10% tension) increases the degree of order slightly. The first stage of energy release, below 120 °C, is probably due to rapid reordering assisted by vacancies created during deformation. The second stage represents the bulk of the reordering and some recovery involving rearrangement and annihilation of dislocations. The deformed specimens are probably strain-aged and thus recovery is accompanied by the dispersal of atmospheres of zinc which increases resistivity and decreases density, to some extent counteracting the effects of recovery. The balance of these three processes in stage 2 causes complex behaviour, the magnitude and even the sign of some changes in properties varies with the deformation. Reordering is complete before the beginning of the third stage of further recovery and recrystallization, in which dispersal of atmospheres is again important. Comparison of measurements of energy, resistivity and density suggests that the high concentration of stacking faults contributes to the resistivity. Anneal hardening is observed for the higher deformations and the maximum hardness coincides with the maximum degree of order.

In-situ EBSD study of the degradation behavior in a type 316 Austenitic Stainless Steel during plastic deformation

2021 ◽  
pp. 030932472098493
Author(s):  
Xiao Wang ◽  
Yuetao Zhang ◽  
Huaying Li ◽  
Ming-yu Huang
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Tensile Deformation ◽  
Target Surface ◽  
Local Orientation ◽  
Deformation Degree ◽  
Band Contrast

Type 316 steels have been heavily utilized as the structural material in many construction equipment and infrastructures. This paper reports the characterization of degradation in 316 austenitic stainless steel during the plastic deformation. The in-situ EBSD results revealed that, with the increase of plastic strain, the band contrast (BC) value progressively decreased in both grain and grain boundaries, and the target surface becomes uneven after the plastic tensile, which indicates that the increase of surface roughness. Meanwhile, the KAM and ρGND values are low in the origin specimen but increased significantly after the in-situ tensile. The results indicated that the KAM and ρGND are closely related to the deformation degree of the materials, which can be used as the indicator for assessing the degradation of 316 steel. Besides, the re-orientation of grain occurred after the tensile deformation, which can be recognized from the lattice orientation and local orientation maps.

STUDYING OF SPACE WEATHER ELECTROMAGNETIC PARAMETERS OF IONOSPHERE IN «OBSTANOVKA 1-STEP» EXPERIMENT ON THE RUSSIAN SEGMENT OF THE ISS

2021 ◽  
pp. 20-41
Author(s):  
Stanislav I. KLIMOV ◽  
Valery A. GRUSHIN Valery A ◽  
Kalman BALAJTHY ◽  
Dichko Enchev BACHVAROV ◽  
Serhiy M. BELYAEV ◽  
...  
Keyword(s):  
Plasma Wave ◽  
Space Weather ◽  
Space Station ◽  
Scientific Instrument ◽  
Surface Zone ◽  
Electromagnetic Parameters ◽  
Wave Processes ◽  
Near Surface ◽  
Ionosphere Plasma ◽  
Electric And Magnetic Fields

The program and results of physical research in the international (5 countries) space experiment «The situation (1 stage)», conducted onboard the Russian segment of the International Space Station (ISS) in the period 27.02.2013 to 09.05.2015, is presented. The methods and scientific tasks of the experiment and the composition of the Plasma-wave complex based on the combined wave diagnostics method are described in detail, and designed to conduct geophysical studies through long-term monitoring measurements of the electromagnetic parameters of the ionosphere plasma and plasma-wave processes associated with the manifestation in the ionosphere of the solar-magnetosphere-ionosphere and ionosphere-atmosphere relationships, i. e., parameters of space weather. Studies in the near-surface zone of plasma-wave processes of interaction of an extra-large spacecraft, like ISS, with the ionosphere are necessary for both applied and fundamental geophysical studies. The electric and magnetic fields and currents measured at the surface of the ISS are determined by the parameters of the surrounding ionosphere plasma and the nature of the interaction of the materials on the surface with this medium. Key words: orbital space station, fundamental space research, ionosphere plasma, plasma-wave processes, electromagnetic fields and radiation, scientific instrument, space weather.

scholarly journals Modern Geodetic Measurement Techniques in Gravimetric Studies on the Example of Gypsum Karst in the Siesławice Region

2018 ◽  
Vol 35 ◽  
pp. 03002 ◽  
Author(s):  
Sławomir Porzucek ◽  
Monika Łój ◽  
Karolina Matwij ◽  
Wojciech Matwij
Keyword(s):  
Laser Scanning ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Digital Terrain Model ◽  
Field Studies ◽  
Surface Zone ◽  
Three Dimensional Model ◽  
Geodetic Measurement ◽  
Near Surface ◽  
Gypsum Karst

In the region of Siesławice (near Busko-Zdrój, Poland) there are unique phenomena of gypsum karst. Atmospheric factors caused numerous gypsum outcrops, canals and underground voids. The article presents the possibility of using non-invasive gravimetric surveys supplemented with geodetic measurements to illustrate karst changes occurring around the void. The use of modern geodetic measurement techniques including terrestrial and airborne laser scanning enables to generate a digital terrain model and a three-dimensional model of voids. Gravimetric field studies allowed to map the anomalies of the gravitational field of the near-surface zone. Geodetic measurement results have made it possible to accurately determine the terrain correction that supplemented the gravimetric anomaly information. Geophysical interpretation indicate the presence of weathered rocks in the near surface zone and fractures and loosened zones located surround the karst cave.

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