●Member

　Masaaki Tabuchi (GL), Kazuhiro Kimura, Hiromichi Hongo, Takashi Watanabe, Kota Sawada

●Mission To clarify the mechanisms of degradation of material properties and damage evolution under long-term creep  conditions and to accumulate the life prediction systems using damage mechanics and fracture mechanics for the  advanced heat resisting steels and structural components used in the next generation nuclear power plants and high  efficiency thermal power plants. ●Outline 　　１．Evaluation system for microstructural change during long-term creep 　　　　・precipitation behavior (precipitation site, size distribution, number density, TTP diagram） 　　　　・precipitation and disappearance process for strengthening and harmful phases 　　　　・simulation for microstructural change 　　２．Evaluation system for damage evolution in welded component      　　・evaluation technique of damage evolution in component 　　　　・simulation system for damage evolution by damage and fracture mechanics 　　　　・effect of damage area and multiaxial stress on fracture property 　　３．Life evaluation system for material and component 　　　　・life prediction method containing meso scale microstructural change ●Recent topics 　　・Retardation of Type IV damage by boron 　　・Visualization of Z phase after long-term creep

●Papers

2006年

1. M. Tabuchi, J. C. Ha and A. T. Yokobori, Jr.：Creep Crack Growth Properties of Welded Joints for 12Cr Ferritic Steel, Strength, Fracture and Complexity, Vol.4 No.1 (2006) pp.47-54.
2. M. Tabuchi, H. Hongo, T. Watanabe and A. T. Yokobori, Jr.：Creep Crack Growth Analysis of Welded Joints for High Cr Heat Resisting Steel, J. of ASTM International, Vol.3, No.5 (2006) pp.1-9.
3. M. Kondo, M. Tabuchi, S. Tsukamoto, F. Yin and F. Abe：Suppressing Type IV Failure via Modification of heat Affected Zone Microstructures Using High Boron Content in 9Cr Heat Resistant Steel Welded Joints, Science and Technology of Welding and Joining, 11 (2006) pp.216-223.
4. T. Watanabe, M. Tabuchi, M. Yamazaki, H. Hongo and T. Tanabe：Creep Damage Evaluation of 9Cr-1Mo-V-Nb Steel Welded Joints Showing Type IV Fracture, International Journal of Pressure Vessels and Piping, 83 (2006) pp.63-71.
5. S. K. Albert, M. Matsui, T. Watanabe, H. Hongo, K. Kubo, M. Tabuchi：Creep Behaviour of Weld Joints and Simulated HAZs of a High Cr Ferritic Steel, Transactions of the Indian Institute of Metals, Vol. 59, No.1 (2006) pp. 47-55.
6. 杉浦隆次，横堀寿光，高森新樹，田淵正明，富士彰夫，依田満夫，小林謙一，横堀武夫： W添加9-12%Crフェライト系耐熱鋼におけるクリープき裂成長寿命予測式の高精度化に及ぼす化学成分，材料組織の影響，日本金属学会誌， 70 (2006) pp.452-460.
7. K.Sawada, H.Kushima and K.Kimura：Z-phase formation during creep and aging in 9-12% Cr heat resistant steels, ISIJ International 46 (2006), p.769-775.
8. T.Ohmura, K.Tsuzaki, K.Sawada and K.Kimura：Inhomogeneous nano-mechanical properties in the multi-phase microstructure of long-term aged type 316 stainless steel, J. Mater. Res. 21 (2006), p.1229-1236.

2005年

1. 田淵正明，近藤雅之，本郷宏通，渡部隆，殷福星，阿部冨士雄：ボロン添加による高>Cr耐熱鋼溶接継手のクリープ特性の改善, 材料, 54 (2005) pp.162-167.
2. 本郷宏通，山崎政義，渡部隆，田淵正明，田辺龍彦，門馬義雄：多層溶接継手のクリープ変形挙動に及ぼす溶接金属部の不均一な高温強度特性の影響，材料 , 54 (2005) pp.155-161.
3. S. K. Albert, M. Kondo, M. Tabuchi, F. Yin, K. Sawada, F. Abe：Improving the Creep Properties of 9Cr-3W-3Co-NbV Steels and their Weld Joints by the Addition of Boron, Metallurgical and Materials Transactions A, 36A (2005) pp.333-343.
4. S.K. Albert, M. Tabuchi, H. Hongo, T. Watanabe, K. Kubo and M. Matsui： Effect of welding process and groove angle on type IV cracking behavior of weld joints of a ferritic steel, Science and Technology of Welding and Joining, 10 (2005) pp.149-157.
5. F. Abe, M. Tabuchi, M. Kondo and S. Tsukamoto：Improvement of creep strength of advanced ferritic steel welded joints, Welding in the World, 49 (2005) pp.59-66.
6. J.C. Ha, J.H. Lee, M. Tabuchi and A.T. Yokobori, Jr.：Estimation of Creep Crack Growth Properties using Circumferential Notched Round Bar Specimen for 12CrWCoB Rotor Steel, Key Engineering Materials, 297-300 (2005) pp.397-402.
7. K. Sawada, T. Ohba, H. Kushima and K. Kimura：Effect of microstructure on elastic property at high temperatures in ferritic heat resistant steels, Materials Science and Engineering A394 (2005), p.36-42.
8. K.Sawada, K.Miyahara, H.Kushima, K.Kimura and S.Matsuoka：Contribution of microstructural factors to hardness change during creep exposure in Mod.9Cr-1Mo steel, ISIJ International 45 (2005), p.1934-1939.

2004年

1. M. Tabuchi, J. C. Ha, H. Hongo, T. Watanabe, A. T. Yokobori, Jr.：Experimental and Numerical Study on the Relationship between Creep Crack Growth Properties and Fracture Mechanisms, Metallurgical and Materials Transactions A, 35A (2004) pp.1757-1764.
2. M. Tabuchi, M. Kondo, T. Watanabe, H. Hongo, F. Yin and F. Abe： Improvement of Type IV Cracking Resistance of 9Cr Heat Resisting Steel Weldment by Boron Addition”, Acta Metallurgica Sinica, 17 (2004) pp.331-337.
3. M. Tabuchi, M. Kondo, K. Kubo and S.K. Albert：Improvement of Type IV Creep Cracking Resistance of 9Cr Heat Resisting Steels by Boron Addition, Operation Maintenance and Materials Issues (OMMI), Vol.3, No.3 (2004) pp.1-11.
4. T. Adachi, A. T. Yokobori, Jr., M. Tabuchi, A. Fuji and T. Yokobori：The Proposal of Q* Parameter and Derivation of the Law of Creep Crack Growth Life for a Round Bar Specimen with a Circular Notch for Cr-Mo-V Steel, Materials at High Temperatures, 21 (2004) pp.95-100.
5. 本郷宏通，山崎政義，渡部隆，田淵正明，田辺龍彦，門馬義雄：ミニチュア溶接金属および大形溶接継手試験片による 316FR溶接金属のクリープ特性の評価, 材料, 53 (2004) pp.566-571.
6. T. Watanabe, M. Yamazaki, H. Hongo, M. Tabuchi and T. Tanabe： Effect of Stress on Microstructural Change due to Aging at 823K in Multi-layer Welded Joint of 2.25Cr - 1Mo Steel, International Journal of Pressure Vessels & Piping 81 (2004) pp.279-284.
7. F. Abe and M. Tabuchi：Microstructural and Creep Strength of Welds in Advanced Ferritic Power Plant Steels, Science and Technology of Welding and Joining, 9 (2004) pp.22-30.
8. 渡部隆，山崎政義，本郷宏通，田淵正明，田辺龍彦：9Cr-1Mo-V-Nb鋼溶接継手の長時間クリープにおける Type IV破壊と微細組織, 鉄と鋼, 90 (2004) pp.206-212.
9. S. K. Albert, M. Matsui, H. Hongo, T. Watanabe, K. Kubo and M. Tabuchi：Creep rupture properties of HAZs of a high Cr ferritic steel simulated by a weld simulator, International Journal of Pressure Vessels & Piping, 81 (2004) pp.221-234.
10. J.C. Ha, M. Tabuchi, H. Hongo, A.T. Yokobori, Jr. and A.Fuji：Creep Crack Growth Properties for 12CrWCoB Rotor Steel Using Circular Notched Specimens, International Journal of Pressure Vessels & Piping, 81 (2004) pp.401-407.
11. H. Hongo, M. Yamazaki, T. Watanabe, T. Tanabe, M. Tabuchi and Y. Monma： Evaluation of Creep Properties for 316FR Steel Thick Plate Weldment Using Miniature Creep Specimen, Acta Metallurgica Sinica, 17 (2004) pp.369-374.
12. M. Taneike, K. Sawada and F. Abe：Effect of Carbon Concentration on precipitation Behavior of M₂₃C₆ Carbides and MX Carbonitrides in Martensitic 9Cr Steel During Heat Treatment, Metall. Mater. Trans. 35A (2004), p.1255-1262.
13. K. Sawada, M. Taneike, K. Kimura and F. Abe：Effect of nitrogen content on microstructural aspects and creep behavior in extremely low carbon 9Cr heat-resistant steel, ISIJ International 44 (2004), p.1243-1249.
14. F. Abe, T. Horiuchi, M. Taneike and K. Sawada：Stabilization of martensitic microstructure in advanced 9Cr steel during creep at high temperature, Materials Science and Engineering A378 (2004), p.299-303.
15. K. Sawada, F. Abe and K. Kimura：Deformation behavior of high Cr ferritic steels upon abrupt stress loading, Materials Science and Engineering A387-389 (2004), p.683-686.
16. 澤田浩太, 久保　清, 木村一弘：高Crフェライト鋼の高温での擬弾性挙動解析に基づく組織因子の評価, 鉄と鋼, 90(2004), p.835-840.

2003年

1. M. Tabuchi, M. Matsui, T. Watanabe, H. Hongo, K. Kubo and F. Abe：Creep Fracture Analysis of W Strengthened High Cr Steel Weldment, Materials Science Research International, 9 (2003) pp.23-28.
2. M. Tabuchi, M. Matsui, K. Kubo, T. Watanabe and F. Abe：Microstructures and Creep Fracture Analysis of W strengthened High Cr Steel Weldment, Strength, Fracture and Complexity, 1 (2003) pp.109-116.
3. M. Tabuchi, T. Adachi, A. T. Yokobori, Jr., A. Fuji, J. C. Ha and T. Yokobori：Evaluation of Creep Crack Growth Properties Using Circular Notched Specimens, International Journal of Pressure Vessels & Piping 80 (2003) pp.417-425.
4. 松井正数，田淵正明，渡部隆，久保清，阿部冨士雄：9%Cr系耐熱鋼のHAZ組織とクリープ特性に 及ぼす熱処理の影響, 材料 52 (2003) pp.119-123.
5. S. K. Albert, M. Matsui, T. Watanabe, H. Hongo, K. Kubo and M. Tabuchi：Variation in the Type IV Cracking Behavior of a High Cr Steel Weld with Post Weld Heat Treatment, International Journal of Pressure Vessels & Piping 80 (2003) pp.405-413.
6. A. Fuji, A. T. Yokobori, Jr., M. Kikuchi, M. Tabuchi, and T. Yokobori：Effect of Microstructure on the Characterization of Creep Crack Growth Rate and Rupture in TiAl Inter-metallic Alloys, International Journal of Pressure Vessels & Piping 80 (2003) pp.435-440.
7. K. Sawada, K. Kubo and F. Abe ： Contribution of Coarsening of MX  Carbonitrides to Creep Strength Degradation in High Chromium Ferritic Steel, Materials Science and Technology 19 (2003), p.732-738.
8. K. Sawada, M. Taneike, K. Kimura and F. Abe：In-Situ Observation of Recovery of Lath Structure in 9% Chromium Creep Resistant Steel, Materials Science and Technology 19 (2003), p.739-742.
9. K. Sawada, K. Kimura and F. Abe：Mechanical response of 9%Cr heat-resistant martensitic steels to abrupt stress loading at high temperature, Materials Science and Engineering A358 (2003), p.52-58.
10. M. Taneike, F. Abe and K. Sawada：Creep-strengthening of steel at high temperature using nano-sized carbonitride dispersions, Nature 424 (2003), p.294-296.
11. F. Abe, T. Horiuchi and K. Sawada：High-temperature annealing for maximization of dissolved boron in creep-resistant martensitic 9Cr steel, Materials Science Forum 426-432 (2003), p.1393-1398.