論文 - 小茂鳥　潤

Effect of atmospheric-controlled induction-heating fine particle peening on microstructure and fatigue properties of low-alloy steel

Takesue S., Hayama M., Komotori J.

Fatigue and Fracture of Engineering Materials and Structures （Fatigue and Fracture of Engineering Materials and Structures）  45 （ 10 ） 2908 - 2919 2022年

査読有り,  ISSN  8756758X

　概要を見る

Atmospheric-controlled induction-heating fine particle peening (AIH-FPP) was performed for low-alloy steel, and the effects of the peening temperature, the microstructure of steel, and thermal history during AIH-FPP on the resultant microstructure of treated steel were investigated. Regardless of the prior microstructure and thermal history, the grains near the surfaces were refined by AIH-FPP at peening temperatures from 923 K to 1023 K owing to dynamic recrystallization. To examine the effect of AIH-FPP on the fatigue properties of steel, plane-bending fatigue tests were performed. Compared with the steel mirror-polished, treated with FPP at RT, or only induction-heated, the fatigue properties of steel treated with AIH-FPP were improved. This is because of the formation of a thick and uniform grain-refined layer, the generation of compressive residual stress, and hardening of the surface by AIH-FPP. Moreover, owing to the grain refinement progress, the fatigue properties of steel improved with increasing peening temperature.

• Access to Document (DOI)

Development of AIH-FPP Carburizing Process Using Carbon Powder

Umeno G., Hayama M., Takesue S., Tomita T., Kato T., Misaka Y., Komotori J.

Zairyo/Journal of the Society of Materials Science, Japan （Zairyo/Journal of the Society of Materials Science, Japan）  71 （ 9 ） 787 - 794 2022年

ISSN  05145163

　概要を見る

In this study, the surface of industrial pure iron was treated with atmospheric-controlled induction heating fine particle peening (AIH-FPP) using mechanical coating (MC) particles of carbon/steel obtained by mixing carbon powder and fine steel particles using mechanical milling. The surface modification effect and the mechanism of its effect were examined and considered by analyzing of the treated surface. Results showed that a modified layer in which carbon elements were diffused was formed near the treated surface by the AIH-FPP treatment using MC particles. In addition, by examining the influence of the treatment conditions on the formation of the modified layer by the design of experiments, the treatment temperature showed the most significant influence among the treatment temperature, peening time, and gas flow rate. The higher the treatment temperature, the deeper the carbon diffused layer. In addition, when treated at ≥1273 K, the microstructure near the surface became pearlite, and Vickers hardness increased. The time required for carbon diffusion in the AIH-FPP carburizing process using MC particles of carbon/steel was approximately the same as that of a general carburizing treatment using a reactive gas. In the AIH-FPP carburizing process, carbon is considered to be transferred from the particles to the surface, and the grain boundaries and dislocations increased by fine particle preening (FPP) are used as channels to diffuse inside the specimen. This mechanism is entirely different from the conventional carburizing methods.

• Access to Document (DOI)

Effect of Room Temperature Fine Particle Peening Pretreatment on Grain Refinement of Fe–Cr Alloys by AIH-FPP

Takesue S., Kikuchi S., Komotori J.

Materials Transactions （Materials Transactions）  63 （ 2 ） 203 - 208 2022年

ISSN  13459678

　概要を見る

Fine particle peening (FPP) at room temperature was introduced to create finer grains at the surfaces of Fe–Cr alloys that were then treated by atmospheric controlled induction heating FPP (AIH-FPP). The effect of the proposed treatment on the grain refinement behavior of the alloys was investigated using optical microscopy and micro-Vickers hardness testing. The FPP pretreatment at room temperature increased the effectiveness of the grain refinement via dynamic recrystallization during subsequent AIH-FPP. Grain refinement at the surface of Fe–Cr alloys progressed with an increase in the cycles of the treatment. The addition of Cr in Fe–Cr alloys promotes the formation of fine grains during the treatment. Specimens with fine grains created via static recrystallization were also prepared and compared to grains formed via dynamic recrystallization by the room temperature FPP pretreatment and subsequent AIH-FPP to evaluate the effectiveness of the proposed treatment. The grains formed through dynamic recrystallization by the proposed treatment were finer than those formed through static recrystallization. These results indicate that the proposed combination of room temperature FPP and AIH-FPP is effective for the formation of fine grains at the surfaces of Fe–Cr alloys.

• Access to Document (DOI)

Surface modification of titanium alloy via atmospheric pressure nitrogen plasma assisted femtosecond laser irradiation

K.Katahira, A. Ezura, S.Takeue, J.Komotori

CIRP Annals – Manufacturing, 71   469 - 472 2022年

査読有り

Effect of atmospheric-controlled induction-heating fine particle peening on wear resistance and fatigue properties of maraging steel fabricated by laser powder-bed fusion

Takesue S., Ezura A., Maki Y., Hayama M., Misaka Y., Komotori J.

Journal of Materials Research and Technology （Journal of Materials Research and Technology）  21   373 - 387 2022年

査読有り,  ISSN  22387854

　概要を見る

Maraging steel components fabricated by laser powder-bed fusion, which is a technique of additive manufacturing, are expected to be used widely because of their high strength, hardness and toughness. To apply maraging steel manufactured by laser powder-bed fusion in wider industrial fields and prevent the components from fracture, a study was conducted to improve the wear resistance and fatigue properties of the steel by an atmospheric-controlled induction-heating fine particle peening surface modification technique. The technique developed can create hard intermetallic compound layers and introduce peening effects, which are expected to improve the wear resistance and fatigue properties of maraging steel fabricated by laser powder-bed fusion. The prepared specimens were examined using optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, laser microscopy, X-ray diffraction, micro-Vickers hardness testing, nano-indentation testing, reciprocating ball-on-disk wear tests and axial fatigue tests. It was revealed that atmospheric-controlled induction-heating fine particle peening using mechanically milled particles formed Fe-Al intermetallic compound layers with high hardness, introduced compressive residual stresses and increased the hardness of the maraging steel substrate owing to age hardening. In conclusion, atmospheric-controlled induction-heating fine particle peening can simultaneously improve the wear resistance and fatigue properties of maraging steel fabricated by laser powder-bed fusion within a few minutes. These achievements can expand applications of maraging steel fabricated by laser powder-bed fusion.

• Access to Document (DOI)

浸炭焼入れを施したSCM420H鋼の疲労過程における残留オーステナイトおよび残留応力の変化挙動

羽山元晶，牧悠介， 菊池将一，小茂鳥潤

鉄と鋼 108 （ 11 ） 891 - 899 2022年

最終著者

Development of accurate temperature regulation culture system with metallic culture vessel demonstrates different thermal cytotoxicity in cancer and normal cells

Imashiro C., Takeshita H., Morikura T., Miyata S., Takemura K., Komotori J.

Scientific Reports （Scientific Reports）  11 （ 21466 ）  2021年11月

査読有り

　概要を見る

Hyperthermia has been studied as a noninvasive cancer treatment. Cancer cells show stronger thermal cytotoxicity than normal cells, which is exploited in hyperthermia. However, the absence of methods evaluating the thermal cytotoxicity in cells prevents the development of hyperthermia. To investigate the thermal cytotoxicity, culture temperature should be regulated. We, thus, developed a culture system regulating culture temperature immediately and accurately by employing metallic culture vessels. Michigan Cancer Foundation-7 cells and normal human dermal fibroblasts were used for models of cancer and normal cells. The findings showed cancer cells showed stronger thermal cytotoxicity than normal cells, which is quantitatively different from previous reports. This difference might be due to regulated culture temperature. The thermal stimulus condition (43 °C/30 min) was, further, focused for assays. The mRNA expression involving apoptosis changed dramatically in cancer cells, indicating the strong apoptotic trend. In contrast, the mRNA expression of heat shock protein (HSP) of normal cells upon the thermal stimulus was stronger than cancer cells. Furthermore, exclusively in normal cells, HSP localization to nucleus was confirmed. These movement of HSP confer thermotolerance to cells, which is consistent with the different thermal cytotoxicity between cancer and normal cells. In summary, our developed system can be used to develop hyperthermia treatment.

• Access to Document (DOI)

Effects of particle collision treatments on fatigue strength of Ti-6Al-4V alloy with polishing marks

Morita T., Miyatani A., Takesue S., Kumagai M., Komotori J.

Zairyo/Journal of the Society of Materials Science, Japan （Zairyo/Journal of the Society of Materials Science, Japan）  62 （ 9 ） 1298 - 1303 2021年09月

査読有り,  ISSN  05145163

　概要を見る

In this study, we attempted to nullify the harmful influences of processing marks on the fatigue strength of Ti-6Al-4V alloy by particle collision treatments. As the surface treatments, fine particle bombarding (FPB) and shot peening (SP) were applied to form hardened layers and introduce compressive residual stress. The surface of the objective material was polished to a mirror surface to eliminate the influences of machining on specimens and was then grinded with emery papers (#80) to make uniform processing marks. After the particle collision treatments, the surface conditions, hardness distributions and residual stress were systematically examined, and their relationships with the fatigue strength were considered in detail. On observation of the surfaces, the processing marks were eliminated by the particle collision treatments. At the same time, the surface hardness was increased and high compressive residual stress was introduced. As a result, the fatigue strength was markedly improved by the treatments beyond the level of the material with the processing marks without deterioration of the mechanical properties. The improvement rates of the fatigue strength were high, at 75% by FPB treatment and 58% by SP treatment.

• Access to Document (DOI)

細胞の熱耐性の検討に資する温度制御可能なチタン製培養装置の開発

今城哉裕，井田雄太，宮田昌悟，小茂鳥潤

材料 70 （ 6 ） 479 - 485 2021年06月

査読有り

Formation of Fe–Al intermetallic compound layer by AIH-FPP and its effect on tribological properties of stainless steel

Takesue S., Misaka Y., Komotori J.

ISIJ International （ISIJ International）  61 （ 6 ） 1946 - 1954 2021年06月

査読有り,  ISSN  09151559

　概要を見る

In order to increase the surface hardness and improve the tribological properties of stainless steel, Fe–Al intermetallic compound layers were created by atmospheric-controlled induction-heating fine particle peening (AIH-FPP). The surface microstructure of the stainless steel treated with AIH-FPP was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and micro-Vickers hardness testing. In addition, the tribological properties were investigated by reciprocating ball-on-disk wear tests. When high-speed steel particles coated with thin aluminum layers were used as the shot particles, Fe–Al intermetallic compound layers were formed at the surfaces of the stainless steel with increased heating time during AIH-FPP. This is because aluminum was transferred from the shot particles, and the temperature at the treated surface increased as a result of a combustion synthesis reaction. When the heating temperature after FPP was increased, the transferred aluminum and nitrogen in the atmosphere reacted, which resulted in the formation of aluminum nitrides in addition to Fe–Al intermetallic compounds. The tribological properties of the stainless steel were improved by AIH-FPP since high-hardness layers were created. The results indicate that the formation of an Fe–Al intermetallic compound layer with high hardness by AIH-FPP is effective for modifying the tribological properties of the stainless steel within a relatively short span of time.

• Access to Document (DOI)

Rapid oxynitriding of Ti6Al4V alloy by induction heating in air⁺1

Tamura K., Takesue S., Morita T., Marin E., Komotori J., Misaka Y., Kumagai M.

Materials Transactions （Materials Transactions）  62 （ 1 ） 111 - 117 2021年

査読有り,  ISSN  13459678

　概要を見る

In this study, a rapid oxynitriding technique based on induction-heating was developed for the titanium alloy Ti6Al4V, and its effects on surface characteristics of the alloy were investigated. The surface microstructures of the alloy were characterized by employing a scanning electron microscope, electron back-scatter diffraction, X-ray diffraction and nano-indentation tests. Induction-heating in air for 60 s caused the formation of a hardened layer on the Ti6Al4V alloy surface, which can be attributed to the diffusion of oxygen and nitrogen atoms. When water quenching was performed after heating, transformation to an acicular martensitic ¡A phase occurred, resulting in increased in substrate hardness. However, cracks were initiated at the surface of the oxynitrided alloy. The cracks were eliminated through fine particle bombarding treatment, whereas the hardened layer formed by the oxynitriding treatment remained. The obtained results thus indicate that the oxynitriding technique developed in this study can enhance the wear resistance and tensile strength of the Ti6Al4V alloy within a short period of time.

• Access to Document (DOI)

Ｘ線応力その場測定による鋼表面の圧縮残留応力解放挙動の評価

羽山元晶，菊池将一，小茂鳥潤

鉄と鋼 107 （ 2 ） 137 - 145 2021年

査読有り

Combined effect of gas blow induction heating nitriding and post-treatment with fine particle peening on surface properties and wear resistance of titanium alloy

Takesue S., Kikuchi S., Misaka Y., Morita T., Komotori J.

Materials Transactions （Materials Transactions）  62 （ 10 ） 1502 - 1509 2021年

査読有り,  ISSN  13459678

　概要を見る

In order to fabricate a titanium alloy with superior wear resistance and fatigue strength, fine particle peening (FPP) was introduced as a post-treatment after gas blow induction heating (GBIH) nitriding. The surface characteristics of the treated alloy were examined using X-ray diffraction, scanning electron microscopy, laser microscopy and a micro-Vickers hardness tester. GBIH nitriding and post-treatment with FPP formed nitrided layers with high hardness and compressive residual stress at the surface of the alloy within a short period of time. This is due to the diffusion of nitrogen atoms during GBIH nitriding and plastic deformation of the surface layer during FPP. Reciprocating ball-on-disk wear tests were performed to investigate the wear resistance of the surface-treated alloy. The wear resistance of the titanium alloy was improved by the proposed surface treatment compared with samples that were only polished or FPP-treated. This is due to the presence of a nitrogen compound layer with high hardness at the surface. The abrasiveness toward the wear test counter material was also decreased by the combined surface treatment.

• Access to Document (DOI)

研磨痕を有するTi-6Al-4V合金の疲労強度に及ぼす粒子衝突処理の効果

森田辰郎，宮谷厚志，武末翔吾，熊谷正夫，小茂鳥潤

材料 69 （ 12 ） 915 - 920 2020年12月

査読有り

Rapid nitriding mechanism of titanium alloy by gas blow induction heating

Takesue S., Kikuchi S., Misaka Y., Morita T., Komotori J.

Surface and Coatings Technology （Surface and Coatings Technology）  399 2020年10月

共著, 査読有り,  ISSN  02578972

　概要を見る

This work characterized the surface-modified layers generated on a titanium alloy during gas blow induction heating (GBIH), so as to elucidate the rapid nitriding mechanism. The surface microstructures of GBIH nitrided specimens were analyzed by X-ray diffraction, micro-Vickers hardness testing, scanning electron microscopy and X-ray photoelectron spectroscopy. The data indicate that applying this process for only several minutes can forms nitrided layers on Ti-6Al-4V alloy surfaces, the characteristics of which are similar to those of layers produced by ordinary gas nitriding for several hours. The temperature inside the material was determined to be higher than that on the surface during GBIH nitriding. However, the thickness of the nitrided layer exceeded the estimated value based on the diffusion coefficient at this high internal temperature. This especially thick nitrided layer can possibly be attributed to eddy currents generated in the metal by the application of a high-frequency current. Passivation films on the surface of the Ti-6Al-4V alloy were found to be removed during GBIH nitriding, which is ascribed to the diffusion of oxygen atoms in the passivation film into the substrate. Thus, the data show that GBIH nitriding is able to modify a Ti-6Al-4V alloy within a short period of time based on the effect of an eddy current and the disappearance of the passivation film.

• Access to Document (DOI)

Rapid oxynitriding of Ti-6Al-4V alloy by induction heating in air

Tamura K., Takesue S., Morita T., Marin E., Komotori J., Misaka Y., Kumagai M.

Zairyo/Journal of the Society of Materials Science, Japan （Zairyo/Journal of the Society of Materials Science, Japan）  69 （ 8 ） 605 - 611 2020年08月

ISSN  05145163

　概要を見る

© 2020 Society of Materials Science Japan. All rights reserved. In this study, a rapid oxynitriding technique based on induction heating was developed for the titanium alloy Ti-6Al-4V, and its effects on surface characteristics of the alloy were investigated. The surface microstructures of the alloy were characterized by employing a scanning electron microscope, electron back-scatter diffraction, X-ray diffraction and nano-indentation tests. Induction-heating in air for 60 s caused the formation of a hardened layer on the Ti-6Al-4V alloy surface, which can be attributed to the diffusion of oxygen and nitrogen atoms. When water quenching was performed after heating, transformation to an acicular martensitic α’ phase occurred, resulting in increased in substrate hardness. However, cracks were initiated at the surface of the oxynitrided alloy. The cracks were eliminated through fine particle bombarding treatment, whereas the hardened layer formed by the oxynitriding treatment remained. The obtained results thus indicate that the oxynitriding technique developed in this study can enhance the wear resistance and tensile strength of the Ti-6Al-4V alloy within a short period of time.

• Access to Document (DOI)

AIH-FPPシステムを用いた投射粒子成分の移着と拡散による金属間化合物の創成

武末翔吾，渡邊一敬，三阪佳孝，小茂鳥潤

砥粒加工学会誌 64 （ 8 ） 421 - 427 2020年08月

Influences of particle collision treatments on surface characteristics and fatigue strength of Ti-6Al-4V alloy

Morita T., Miyatani A., Kariya S., Kumagai M., Takesue S., Komotori J.

Results in Materials （Results in Materials）  7 2020年08月

　概要を見る

In this study, the particle collision treatments (fine particle bombarding (FPB) and conventional shot peening (SP)) were performed for Ti–6Al–4V alloy in order to comprehensively investigate the influences of their treatment conditions on the surface conditions, microstructures, hardness distributions and residual stress. Moreover, we examined the relationship between the surface characteristics of the treated materials and their mechanical properties including fatigue strength in detail. According to the obtained experimental results, the values of the maximum height waviness increased with increasing in the size of collision particles and injection pressure. Among all the treated materials, the differences in hardness distribution were relatively small because the work hardening exponent of Ti–6Al–4V alloy is low and the degree of work hardening is insensitive to the amount of plastic deformation. The absolute values of compressive residual stress generated at the surfaces became higher when finer particles were used as collision particles. The increase in injection pressure increased the surface temperature and released the introduced residual stress. As the particle collision treatments affected only the surface regions, the mechanical properties of the treated materials were almost the same as those of the annealed one. In the range of the conditions examined in this study, the most effective treatment to improve the fatigue strength of Ti–6Al–4V alloy was FPB under a relatively low injection pressure. This was because the value of the maximum height waviness was the smallest and the highest compressive residual stress was introduced at the same time.

• Access to Document (DOI)

Characterization of surface layer formed by gas blow induction heating nitriding at different temperatures and its effect on the fatigue properties of titanium alloy

Takesue S., Kikuchi S., Akebono H., Morita T., Komotori J.

Results in Materials （Results in Materials）  5 2020年

研究論文（学術雑誌）, 共著

　概要を見る

Gas blow induction heating (GBIH) nitriding was carried out for Ti–6Al–4V alloy at different temperatures, and its effect on surface characteristics, wear resistance and fatigue properties was investigated. The microstructures of the specimen surface were characterized using optical microscopy, laser microscopy, X-ray diffraction, micro-Vickers hardness tester, and nano-indentation tester. It was found that the surface characteristics of titanium alloy varied with increasing the treatment temperature of GBIH-nitriding. In this study, a nitrogen diffusion layer was formed on the titanium alloy surface GBIH-nitrided at 1073 ​K. A nitrogen compound layer and diffusion layer were created at the treatment temperature of 1173 ​K, which suppressed the wear loss to under one tenth that of the substrate. In order to examine the fatigue properties of the treated alloy, fatigue tests under four-point bending were performed. The fatigue strength of the Ti–6Al–4V alloy GBIH-nitrided at 1173 ​K was 234 ​MPa lower than that of the mirror-polished alloy. The decrease in the fatigue strength is due to the formation of the compound layer with a Young's modulus approximately twice that of the substrate, and the grain coarsening from 7 ​μm to 300 ​μm. The results indicate that a thick nitrided layer with high hardness and the close Young's modulus to the substrate improved the fatigue strength of the Ti–6Al–4V alloy.

• Access to Document (DOI)

Generation of biocompatible titanium alloy surfaces including calcium and phosphorus elements by laser-induced mist spraying wet treatment

Ezura A., Katahira K., Komotori J.

International Journal of Automation Technology （International Journal of Automation Technology）  14 （ 4 ） 575 - 581 2020年

ISSN  18817629

　概要を見る

© 2020, Fuji Technology Press. All rights reserved. Titanium alloys are widely used for the hard tissue substitute implants. However, it is necessary to improve interfacial biocompatibility to reduce adhesion period. For improvement of biocompatibility of Ti-6Al-4V ELI alloys, texture and chemical composition on contact part with biological tissue play very important roles. In this research, micro texture was generated on the Ti-6Al-4V ELI alloy surfaces utilizing laser irradiation, in order to improve biocompatibility. The biocompatibility was evaluated by osteoblast cell culture assays. The results indicated the surface having micro texture improve biocompatibility as com-pared with untreated surface. This was considered in order the fact that the formed modified surface had hydrophilicity, thereby improving the cell compatibility, and the cell adhesion due to the complicated shape. In addition, mist of glycerophosphoric acid calcium aqueous solution was applied on the laser irradiated area. As result, micro texture including Ca and P elements was generated on the Ti-6Al-4V ELI alloy surfaces. When laser was irradiated, glycerophosphoric acid calcium aqueous solution was applied as mist flowed on the test pieces as droplet. The velocity of droplet fluid was relatively fast, so that laser irradiation was unhindered access to the surface of test pieces and the treatment was stable. In order to estimate biocompatibility, culture assays using osteoblast cells were conducted on the treated surface having micro texture including Ca and P elements. As results, it was clearly that biocompatibility of the specimen treated by laser with glycerophosphoric acid calcium aqueous solution mist more improved than either untreated specimen or treated specimen soaked in glycerophos-phoric acid calcium aqueous solution.

• Access to Document (DOI)