Abstract：After adding a small amount of Ti into the molten Fe-36Ni Invar alloy, TiC particulates formed in-situ. The yielding strength and the ultimate strength of the strengthened Invar alloy with a small amount of Ti rise about 10% individually compared with the Invar alloy without any alloying element, and both the ductility and the thermal expansion coefficient remain about the same. Particulates ranging from tens of nanometers to hundreds of nanometers were observed by the transmission electronic microscope. These particulates have spherical or ellipsoidal shapes, and combine well with the matrix. According to the relationship between the camera constant and the interplanar spacing, these particulates are determined to be TiC. The standard free energy of formation of TiC is lower than which of Ni3Ti. The Orowan strengthen is considered to be the main strengthen mechanism.
Marqusee JA and Ross J. Theory of Ostwald ripening: Competitive growth and its dependence on volume fraction [J]. J. Chem. Phys., 1984, 80(1): 536-543
[1]
Lement BS, Averbach BL and Cohen M. The dimensional behavior of Invar [J]. Trans A.S.M., 1951, 43:1072-1097
[3]
Nissan SI, Komen Y, and Weiss BZ. An electron microscopy study of the precipitation in an Invar-3.31 at.% Sn alloy [J]. Acta Metall., 1975, 23:1313-1320
[8]
Epner M and Gregory E. Some properties and metallography of steel-bounded titanium carbide [J]. TMS-AIME, 1960, 28:117
[9]
Jiang WH, Fei J and Han XL. In situ formed (TiW)C phase in iron matrix [J]. Metall. Mater. Trans A, 2001, 32A:431-433
[6]
Mazaud JC, and Vial A. Metallographie de la precipitadion a 700°C dans un alliage Fe-40% Ni contenant du beryllium [J]. Acta Met., 1971, 19:1133-1141
[10]
Raghunath C, Bhat MS and Rohatgi PK. In situ technique for synthesizing Fe-TiC composites [J]. Scripta Metall. Mater., 1995, 32(4):577-582
[14]
Jiang WH, Pan WD, Song GH, and Han XL. In-situ Formation of TiC/Hadfield Steel Composites [J]. J. Mater. Sci. Lett., 1998, 17:1527-1529
[18]
Sagaradze VV, Morozov SV, Shabashov VA, Romashev LN and Kuznetsov RI. Dissolution of the spherical and platelike intermetallics in Fe-Ni-Ti austenitic alloys during cold plastic deformation [J]. Phys. Met. Metall., 1988, 66(2):111-120
[20]
Turkdogan ET. Physical Chemistry of High Temperature Technology [M]. New York (US): Academic Press, 1980
[22]
Tong XC and Fang HS. Al-TiC composites In situ-processed by ingot metallurgy and rapid solidification technology: Part II. Mechanical behavior [J]. Metall. Mater. Trans. A., 1998, 29A:893-902
[2]
Ustinovshikov Y, Shabanova I. A study of microstructures responsible for the emergence of the invar and permalloy effects in Fe-Ni alloys [J]. Journal of Alloys and Compounds, 2013, 578:292-296
Leitch K and Chaturvedi M. Aging behavior of Fe-30 Ni alloys containing niobium [J]. Met Trans., 1971, 2:1407-1413
[7]
Gulyaev AA and Svistunova EL. Precipitation process and age-hardenability of Fe-Ni-Be Invar alloys [J]. Scripta Metallurgica et Materialia, 1995, 33(9):1497-1503
[11]
Jiang WH, Pan WD, Song GH and Han XL. In-situ synthesis of a TiC-Fe composite in liquid iron [J]. J. Mater. Sci. Lett., 1997, 16:1830-1832
[13]
Terry BS and Chinyamakobvu OS. In situ production of Fe-TiC composites by reactions in liquid iron alloys [J]. J. Mater Sci. Lett., 1991, 10:628-629
[15]
Do?an ?N, Hawk JA and Schrems KK. TiC-reinforced cast Cr steels [J]. J. Mater. Eng. Perform., 2006, 15(3):320-327
[16]
Liu ZS and Fredriksson H. On the precipitation of TiC in liquid iron by reactions between different phases [J]. Metall. Mater. Trans. A., 1997, 28A:471-483
[19]
Skolianos S, Kattamis TZ, Chen M and Chamber BV. Cast microstructure and tribological properties of particulate TiC-reinforced Ni-base or stainless steel matrix composites [J]. Mater. Sci. Eng., 1994, A183:195-204
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