scholarly journals Effect of Grain Size on Change in Surface Roughness of Carbon Steels Through Polishing Processes

2022 ◽  
Vol 16 (1) ◽  
pp. 95-103
Author(s):  
Masaaki Matsuzawa ◽  
Atsushi Ito ◽  
Takafumi Komatsu ◽  
Shiro Torizuka ◽  
◽  
...  
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Vickers Hardness ◽  
Size Control ◽  
Considerable Effect ◽  
Carbon Steels ◽  
Coarse Grained ◽  
Mirror Surface ◽  
Ultrafine Grained ◽  
Metallic Parts

A mirror-like reflecting surface is an important characteristic in many industrial metallic parts. Polishing is done to form a mirror surface on metals. However, the effect of the grain size of metals on surface roughness through polishing processes is not clear. Specifically, mirror surface formation of ultrafine grained materials is still unknown. Ultrafine grained steels and coarse grained steels with 0.02, 0.10, and 0.60 wt% carbon contents were prepared by warm caliber rolling and annealing. Average grain sizes were 1–2 μm and 4–40 μm. The changes in surface roughness, Sa, were measured with an atomic force microscope (AFM) via eight polishing steps, using emery papers of type #600, #1000, #1500, #2000, #2500, #4000, and free abrasive grains of 3 μm and 1 μm diamond. As the polishing process progressed, the surface unevenness was removed and the surface roughness, Sa, decreased in all steels. The differences of Sa at each polishing step were analyzed from the point of carbon content, Vickers hardness, and grain size. Carbon contents and Vickers hardness have little effect on Sa. However, grain size has a considerable effect on Sa in all steels. Ultrafine grained steels have smaller Sa in all polishing steps in all steels. This is because ultrafine grained steels have very small work hardening rate. After final polishing, Sa is 2.5–3.6 nm in coarse grained steels and 2.0–2.6 nm in ultrafine grained steels. To obtain a mirror surface with smaller Sa, grain size control is important.

Unique Mechanical Properties of Nanostructured Metals

2007 ◽  
Vol 7 (11) ◽  
pp. 3765-3770 ◽  
Author(s):  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Equivalent Strain ◽  
Coarse Grained ◽  
Roll Bonding ◽  
Nanostructured Metals ◽  
Ultrafine Grained ◽  
Nanocrystalline Structures ◽  
Rolling Deformation

Recently, it becomes possible to fabricate bulk metals having ultrafine grained or nanocrystalline structures of which grain size is in nano-meter dimensions. One of the promising ways to realize bulk nanostructured metals is severe plastic deformation (SPD) above logarithmic equivalent strain of 4. We have developed an original SPD process, named Accumulative Roll Bonding (ARB) using rolling deformation in principle, and have succeeded in fabricating bulk nanostructured sheets of various kinds of metals and alloys. The ARB process and the nanostructured metals fabricated by the ARB are introduced in this paper. The nanostructured metals sometimes perform quite unique mechanical properties, that is rather surprising compared with conventionally coarse grained materials. The unique properties seem to be attributed to the characteristic structures of the nano-metals full of grain boundaries.

scholarly journals Nanoindentation-Induced Pile-Up in the Residual Impression of Crystalline Cu with Different Grain Size

2017 ◽  
Author(s):  
Jiangjiang Hu ◽  
Weiming Sun ◽  
Taihua Zhang ◽  
Yusheng Zhang
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Room Temperature ◽  
Indentation Depth ◽  
Dislocation Motion ◽  
Coarse Grained ◽  
Ultrafine Grained ◽  
Pile Up ◽  
Different Grain Size ◽  
Multiple Slips

At room temperature, the indentation morphologies of crystalline copper with different grain size including nanocrystalline (NC), ultrafine-grained (UFG) and coarse-grained (CG) copper were studied by nanoindentation at the strain rate of 0.04/s without holding time at indentation depth of 2000 nm. As the grain size increasing, the height of the pile-up around the residual indentation increases and then has a slightly decrease in the CG Cu, While the area of the pile-up increases constantly. Our analysis has revealed that the dislocation motion and GB activities in the NC Cu, some cross- and multiple-slips dislocation insides the larger grain in the UFG Cu, and forest dislocations from the intragranular Frank-Read sources in the CG Cu, would directly induce these distinct pile-up effect.

scholarly journals Material microstructure effects in micro-endmilling of Cu99.9E

2016 ◽  
Vol 232 (7) ◽  
pp. 1143-1155 ◽  
Author(s):  
AM Elkaseer ◽  
SS Dimov ◽  
DT Pham ◽  
KP Popov ◽  
L Olejnik ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Chip Thickness ◽  
Micro Milling ◽  
Coarse Grained ◽  
Material Microstructure ◽  
Micro Cutting ◽  
Minimum Chip Thickness ◽  
Average Grain Size ◽  
Material Homogeneity

This article presents an investigation of the machining response of metallurgically and mechanically modified materials at the micro-scale. Tests were conducted that involved micro-milling slots in coarse-grained Cu99.9E with an average grain size of 30 µm and ultrafine-grained Cu99.9E with an average grain size of 200 nm, produced by equal channel angular pressing. A new method based on atomic force microscope measurements is proposed for assessing the effects of material homogeneity changes on the minimum chip thickness required for a robust micro-cutting process with a minimum surface roughness. The investigation has shown that by refining the material microstructure the minimum chip thickness can be reduced and a high surface finish can be obtained. Also, it was concluded that material homogeneity improvements lead to a reduction in surface roughness and surface defects in micro-cutting.

Structure and Fatigue Properties of the Mg Alloy AM60 Processed by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 803-808 ◽  
Author(s):  
Rinat K. Islamgaliev ◽  
Olya B. Kulyasova ◽  
Bernhard Mingler ◽  
Michael Zehetbauer ◽  
Alexander Minkow
Keyword(s):  
Grain Size ◽  
Endurance Limit ◽  
Volume Fraction ◽  
Coarse Grained ◽  
Fatigue Properties ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Mean Grain Size ◽  
Fatigue Endurance ◽  
Misorientation Angles

This paper reports on the microstructures and fatigue properties of ultrafine-grained (UFG) AM60 magnesium alloy processed by equal channel angular pressing (ECAP) at various temperatures. After ECAP processing, samples exhibited an increase in fatigue endurance limit, which correlates well with a decrease in grain size. In case of lowest ECAP temperature, the mean grain size is as small as 1 2m which leads to an increase in fatigue endurance limit by 70 % in comparison to coarse-grained alloy. The temperature of ECAP not only governs the grain size and misorientation angles of grain boundaries but also the volume fraction of precipitates, thus affecting the probability of twinning and grain growth after fatigue treatment.

Fabrication and Characterization of Bulk Nanocrystalline Layer on Steel Components With Different Microstructures by Air Blast Shot Peening

2010 ◽  
Author(s):  
R. Waikar ◽  
Y. B. Guo
Keyword(s):  
Electron Microscopy ◽  
Surface Roughness ◽  
Grain Size ◽  
Bulk Material ◽  
Lower Surface ◽  
Carbon Steels ◽  
Sem Images ◽  
Cross Sectional ◽  
Nano Crystalline ◽  
Bulk Nanocrystalline

The fabrication of nano-crystalline (NC) layers in pearlitic and martensitic carbon steels viz. AISI 1018, 1045 and 1075 alloys using ABSP has been studied. The cross-sectional microstructure of the samples showed that a gradual reduction of the grain size near the surface until a clearly demarcated NC layer was observed. The NC layers were characterized using optical, scanning electron microscopy (SEM), transmission electron microscopy (TEM), microhardness and nanohardness measurements. 2D surface topography of the peened surface was also carried out to measured surface roughness. The roughnesses of the peened surfaces were dependent on the hardness of the sample. Samples with higher hardness had lower surface roughness value. NC layers varying from 5 to 15 μm were observed using the optical and SEM images in the different types of steels. The SEM images clearly showed the dissolution of cementite phase in the NC layers. The nanohardness measurements of the steels showed that the NC layers had much higher hardness than the bulk material. The microhardness measurements also confirmed the mentioned phenomena. A TEM study was carried out on the NC layer and the grain size was confirmed to be 50 to 80 nm.

The Effects of Nanostructure on the Strengthening of NiAl

1998 ◽  
Vol 552 ◽  
Author(s):  
T. Chen ◽  
N. N. Thadhani ◽  
J. M. Hampikian
Keyword(s):  
Grain Size ◽  
Vickers Hardness ◽  
High Energy ◽  
Coarse Grained ◽  
Shock Compaction ◽  
Transmission Electron ◽  
Nial Alloy ◽  
Microhardness Testing ◽  
The Relationship ◽  
Hardness Values

ABSTRACTThe relationship between microhardness and grain size was investigated for nanocrystalline and coarse-grained stoichiometric intermetallic NiAl. The nanocrystalline NiAl specimens were synthesized through mechanical alloying with a high-energy Spex 8000 shaker mill and consolidated by shock compaction at a peak pressure of 4–6 GPa, to 83% dense compacts. The nanocrystalline NiAl compacts were also sintered at 1073, 1173 and 1473 K for 2 h. The Vickers hardness of consolidated and sintered NiAl was determined by microhardness testing, and the grain size and microstructure were investigated with transmission electron microscopy. It was found that the hardness values increased with decreasing grain size of the NiAl alloy. The Vickers hardness values were approximately 650±16, 690±6, 800±43 HV, respectively for NiAl with grain-sizes corresponding to approximately 27±18, 11±6 and 9±6 nm. The possible strengthening mechanisms operating in NiAl are discussed.

Deformation Behavior of Ultrafine Grained Iron

2006 ◽  
Vol 503-504 ◽  
pp. 317-322 ◽  
Author(s):  
Setsuo Takaki ◽  
Kenji Kawasaki ◽  
Y. Futamura ◽  
Toshihiro Tsuchiyama
Keyword(s):  
Grain Size ◽  
Dislocation Density ◽  
Yield Stress ◽  
Grain Refinement ◽  
Work Hardening ◽  
Coarse Grained ◽  
Deformation Condition ◽  
Initial Yield Stress ◽  
Ultrafine Grained ◽  
Dislocation Strengthening

Work hardening behavior and microstructure development during deformation by cold rolling were investigated in iron with different grain size. Grain refinement makes the introduction of dislocation easier. For instance, under the same deformation condition (5% reduction in thickness), dislocation density is the order of 1014m-2 in a coarse grained material (mean grain size; 20μm), while it reaches 7×1015m-2 in an ultrafine grained material (0.25μm). It is well known that the yield stress of metals is enlarged with an increase in dislocation density on the basis of the Bailey-Hirsch relationship. However, it should be noted that the ultrafine grained material never undergoes usual work hardening although the dislocation density is surely enhanced to around the order of 1016m-2: 0.2% proof stress is almost constant at 1.4 ~ 1.5GPa regardless of the amount of deformation. The dislocation density of 1016m-2 is thought to be the limit value which can be achieved by cold working of iron and the yield stress of iron with this dislocation density (ρ) is estimated at 1.1GPa from the Bailey-Hirsch relationship; σd [Pa] = 0.1×109 + 10 ρ1/2. On the other hand, yield stress of iron is enhanced by grain refinement on the basis of the Hall-Petch relationship; σgb [Pa] = 0.1×109 + 0.6×109 d-1/2 as to the grain size d [μm]. This equation indicates that the grain size of 0.35 μm gives the same yield stress as that estimated for the limit of dislocation strengthening (1.1GPa). As a result, it was concluded that work hardening can not take place in ultrafine grained iron with the grain size less than 0.35 μm because dislocation strengthening can not exceed the initial yield stress obtained by grain refinement strengthening.

Investigation on Grain Size Effect of Rolling Texture in Copper

2016 ◽  
Vol 850 ◽  
pp. 857-863 ◽  
Author(s):  
Yao Jiang ◽  
Jing Tao Wang ◽  
Yue Wang ◽  
Jian Yin
Keyword(s):  
Grain Size ◽  
Cold Rolling ◽  
Size Effect ◽  
Rolling Texture ◽  
Coarse Grained ◽  
Grain Size Effect ◽  
Shear Texture ◽  
Ecap Pass ◽  
Ultrafine Grained ◽  
Pole Figures

Cold rolling (CR) was conducted on coarse grained (CG) and ultrafine-grained (UFG) coppers, obtained by 1 and 8 passes in the equal channel angel pressing (ECAP), to investigate the effect of grain size on rolling texture. The microstructure was refined to UFG (~420 nm) with the ECAP pass increased to 8, while only band-like CG microstructure was observed in the 1 pass processed copper. The influence of the texture before CR could be excluded as the crystallographic texture kept similar for different ECAP pass. Pole figures (PFs) showed that the shear texture introduced by ECAP was replaced by rolling texture after CR. Furthermore, the rolling texture was a kind of classical copper-type for the CG copper, while a brass-type rolling texture was observed in the UFG copper. TEM results confirmed that the deformation nanotwins were only observed in the UFG copper, while the microstructure of CG copper was further compressed and subdivided. It indicated that the observed differences in rolling texture component and density might be contributed to the grain size effect which resulted in different deformation mechanism and grain subdivision behavior.

Deformation Mechanisms in Ultrafine-Grained Zn at Different Strain Rates and Temperatures

2013 ◽  
Vol 592-593 ◽  
pp. 313-316
Author(s):  
Péter Jenei ◽  
Guy Dirras ◽  
Jenő Gubicza ◽  
Hervé Couque
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Strain Rate Range ◽  
Deformation Mechanisms ◽  
Coarse Grained ◽  
Strain Rates ◽  
Initial State ◽  
Rate Range ◽  
Hexagonal Close Packed ◽  
Ultrafine Grained

The deformation mechanisms in ultrafine-grained hexagonal close packed Zn were investigated at different strain rates and temperatures. The influence of grain size on the deformation mechanisms was revealed by comparing the results obtained on ultrafine-grained and coarse-grained Zn. It was found that for coarse-grained Zn at room temperature and strain rates lower than 10-2s-1twinning contributed to plasticity besides dislocation activity. For strain rates higher than 103s-1the plasticity in coarse-grained Zn was controlled by dislocation drag. In ultrafine-grained Zn the relatively large dislocation density (~1014m-2) and the small grain size (~250 nm) limit the dislocation velocity yielding the lack of dislocation drag effects up to 104s-1. For ultrafine-grained Zn, twinning was not observed in the entire strain rate range due to its very small grain size. During room temperature compression at strain rates higher than 0.35 s-1and in high temperature creep deformation of ultrafine-grained Zn besides prismatic and pyramidal <c+a> dislocations observed in the initial state, <a>-type basal and pyramidal dislocations as well as other <c+a>-type pyramidal dislocations were formed.

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