Solution and aging behavior of precipitates in laser melting deposited V-5Cr-5Ti alloys

Abstract

V-5Cr-5Ti alloys have been fabricated using a laser melting deposition (LMD) additive manufacturing process, showing precipitates aggregated near the grain/dendrite boundaries. Since the mechanical properties of vanadium alloys considerably depend on the precipitates, solution and aging treatments have been applied to eliminating the aggregations of the precipitates. The results show that as the solution temperature increases from 800 to 1560 °C, the densities and the lengths of the precipitates are reduced, while the widths of the precipitates are increased. When the solution temperature reaches 1560 °C, most impurity elements diffuse into the matrix and form into a nearly uniform supersaturated solid solution. Aging treatments have been applied to the 1560 °C solution treated samples. It shows that as the aging temperature increases from 800 to 1200 °C, the precipitate length increases, and the shapes of precipitates change from near-spherical to lath-like. Compared to 800 and 1200 °C, aging at 1000 °C results in the highest precipitate density. Compared to the LMD and solution-treated samples, the aged samples have the highest micro-hardness, due to the precipitation strengthening.

Keywords

vanadium alloy / additive manufacturing / precipitates / solution and aging treatments

References

[1] SatouM, AbeK, KayanoH. High-temperature deformation of modified V-Ti-Cr-Si type alloys [J]. Journal of Nuclear Materials, 1991, 179(1): 757-761

[2] DiercksD R, LoomisB A. Alloying and impurity effects in vanadium-base alloys [J]. Journal of Nuclear Materials, 1986, 141: 1117-1124

[3] HeoN J, NagasakaT, MurogaT. Recrystallization and precipitation behavior of low-activation V-Cr-Ti alloys after cold rolling [J]. Journal of Nuclear Materials, 2004, 325(1): 53-60

[4] SmithJ P, JohnsonW R, TresterP W. Metallurgical bonding development of V-4Cr-4Ti alloy for the DIII-D radiative divertor program [J]. Journal of Nuclear Materials, 1998, 258: 1420-1424

[5] BoevA O, AksyonovD A, KartamyshevA I, MaksimenkoV N, NelasovI V, LipnitskiiA G. Interaction of Ti and Cr atoms with point defects in bcc vanadium: A DFT study [J]. Journal of Nuclear Materials, 2017, 492(8): 14-21

[6] BarronP J, CarruthersA W, FellowesJ W, JonesN G, PickeringE J. Towards V-based high-entropy alloys for nuclear fusion applications [J]. Scripta Materialia, 2020, 176: 12-16

[7] ShikovA K, ChernovV M, PotapenkoM M, GubkinI N, DrobyshevV A, ZurabovV S. Development of production process and study of low-activity V-(4–5)%Ti-(4–5)%Cr structural alloys for thermonuclear reactors [J]. Metal Science & Heat Treatment, 2004, 46(1112): 497-503

[8] PotapenkoM M, DrobishevV A, FilkinV Y, GubkinI N, MyasnikovV V, NikulinA D, ShingarevE N, VedernikovG P, VotinovS N, ZurabovV S, ZolotarevA B. Manufacture of semifinished items of alloys V-4Ti-4Cr and V-10Ti-5Cr for use as a structural material in fusion applications[J]. Journal of Nuclear Materials, 1996, 233–237: 438-441

[9] MurogaT, NagasakaT, IiyoshiA, KawabataA, SakataM. NIFS program for large ingot production of a V-Cr-Ti alloy [J]. Journal of Nuclear Materials, 2000, 283–287: 711-715

[10] NagasakaT, MurogaT, FukumotoK I, WatanabeH, GrossbeckM L, ChenJ-ming. Development of fabrication technology for low activation vanadium alloys as fusion blanket structural materials [J]. Nuclear Fusion, 2006, 46(5): 618-625

[11] ChutoT, SatouM, HasegawaA, AbeaK, NagasakabT, MurogabT. Fabrication using a levitation melting method of V-4Cr-4Ti-Si-Al-Y alloys and their mechanical properties [J]. Journal of Nuclear Materials, 2002, 307(1): 555-559

[12] KuwabaraT, KurishitaH, HasegawaM. Development of an ultra-fine grained V–1.7mass% Y alloy dispersed with yttrium compounds having superior ductility and high strength [J]. Materials Science & Engineering A, 2006, 417(12): 16-23

[13] BaiL-r, LeG-m, LiuX, LiJ-f, XiaS-q, LiX-yan. Grain morphologies and microstructures of laser melting deposited V-5Cr-5Ti alloys [J]. Journal of Alloys & Compounds, 2018, 745: 716-724

[14] XiaY, DongZ-w, GuoX-y, TianQ-h, LiuY. Towards a circular metal additive manufacturing through recycling of materials: A mini review [J]. Journal of Central South University, 2020, 27(4): 1134-1145

[15] YangL-n, ShanZ-d, RongW-j, LiuF, WangY-wei. Three-dimensional direct writing technology of low melting point molten metal [J]. Three-dimensional Direct Writing Technology of Low Melting Point Molten Metal, 2018, 49(10): 47-54

[16] GellesD S, StubbinsJ F. Microstructural development in irradiated vanadium alloys [J]. Journal of Nuclear Materials, 1994, 212(part-P1): 778-783

[17] GellesD S, RiceP M, ZinkleS J, ChungH M. Microstructural examination of irradiated V-(4-5%)Cr-(4-5%)Ti [J]. Journal of Nuclear Materials, 1998, 258–263: 1380-1385

[18] MurogaT, HeoN J, NagasakaT, WatanabeH, NishimuraA, ShinozakiK. Heterogeneous precipitation and mechanical property change by heat treatments for the laser weldments of V-4Cr-4Ti alloy [J]. Plasma & Fusion Research, 2015, 10: 1405092

[19] ZhuB-l, YangS-w, DingJ-w, ZhangW-h, LongY, WanF-rong. Abnormal hardening effect induced by the lath-like precipitates in the V-4Cr-4Ti alloy [J]. Materials Letters, 2015, 161609-612

[20] ZhuB-l, YangS-w, ZhangM-q, DingJ-w, LongY, WanF-rong. Formation and evolution of platelet-like Ti-rich precipitates in the V-4Cr-4Ti alloy [J]. Mater Charact, 2016, 111: 60-66

[21] ZinkleS J, MatsuiH, SmithD L, RowcliffeA F, VanO E, AbeK, KazakovV A. Research and development on vanadium alloys for fusion applications [J]. Journal of Nuclear Materials, 1998, 258–263(4): 205-214

[22] HoelzerD T, WestM K, ZinkleS J, RowcliffeA F. Solute interactions in pure vanadium and V-4Cr-4Ti alloy [J]. Journal of Nuclear Materials, 2000, 283–287: 616-621

[23] LiZ-d, LinC-g, CuiS. Behavior of secondary phase of As-cast V-5Cr-5Ti alloy [J]. Rare Metal Mat Eng, 2017, 46(1): 104-110(in Chinese)

[24] HeoN J, NagasakaT, MurogaT. Recrystallization and precipitation behavior of low-activation V-Cr-Ti alloys after cold rolling [J]. Journal of Nuclear Materials, 2004, 325(1): 53-60

[25] MurogaaT, ChenJ M, ChernovV M, KurtzR J, FlemM L. Present status of vanadium alloys for fusion applications [J]. Journal of Nuclear Materials: Materials Aspects of Fission and Fusion, 2014, 455(1–3): 263-268

[26] NagasakaT, HeoN J, MurogaT, NishimuraA, WatanabeH, NaruiM, ShinozakiK. Impact properties of NIFS-HEAT-2 (V-4Cr-4Ti) after YAG laser welding and neutron irradiation at 563 K [J]. Journal of Nuclear Materials, 2004, 329–333: 1539-1543

[27] NagasakaT, HeoN J, MurogaT, ImamuraM. Examination of fabrication process parameters for improvement of low-activation vanadium alloys [J]. Fusion Engineering and Design, 2002, 61–62: 757-762

[28] DingJ-w, YangS-w, LiuG-l, LiQ-f, ZhuB-l, ZhangM-q, ZhouL-j, ShangC-j, ZhanQ, WanF-rong. Recrystallization nucleation in V-4Cr-4Ti alloy [J]. Journal of Alloys and Compounds, 2018, 777: 663-672

[29] BuehlerBuehler SumMet-A guide to materials preparation & analysis [M], 20132nd editionGermany, Buehler

[30] HIROSAWA S, OGURI Y, OGURA T, SATO T. Formation mechanisms of precipitate free zones in age-hardenable Al alloys [J]. Material Forum, 2004: 666–671. DOI: http://www.icaa-conference.net/ICAA9/data/papers/GP%2091.pdf.

[31] NishimuraA, IwahoriA, HeoN J, NagasakaT, MurogaT, TanakaS I. Effect of precipitation and solution behavior of impurities on mechanical properties of low activation vanadium alloy [J]. Journal of Nuclear Materials, 2004, 329: 438-441

[32] GrongO, ShercliffH R. Microstructural modelling in metals processing [J]. Progress in Materials Science, 2002, 47(2): 163-282

[33] PorterD A, EasterlingK E, SherifMPhase transformations in metals and alloys [M], 2009, Boca Raton, CRC Press

[34] ChenJ M, MurogaT, NagasakaT, QiuS Y, LiC, ChenY, LiangB, XuZ Y. The mechanical properties of V-4Cr-4Ti in various thermo-mechanical states [J]. Fusion Engineering & Design, 2006, 81(23–24): 2899-2905