STP204: Development of Titanium-Base Alloys for Elevated Temperature Application

    Crossley, F A
    Senior Metallurgist, Armour Research Foundation,

    Carew, W F
    Chief Engineer, Joliet Metallurgical Laboratories, Inc.,

    Kessler, H D
    Supervisor, Metallurgical Division, Titanium Metals Corp. of America,

    Pages: 48    Published: Jan 1957


    Abstract

    Tension, creep-rupture and stability test results for titanium-base alloys are discussed. For clarity the discussion is divided into three parts based upon alloy complexity. A survey of hot tensile properties of binary alloys indicated aluminum to be the best metallic strengthener on a weight per cent basis. Creep-rupture data are reported for the following binary alloys: 2, 4, 6, and 8 per cent aluminum; 2, 7, and 15 per cent chromium; 3, 15, and 30 per cent molybdenum; and 30 per cent vanadium. Stability data for some of these alloys are reported. Considering tensile ductility, creep performance and stability of room temperature tensile ductility upon exposure to elevated creep conditions, alloys showing promise as binary alloys and as bases for the development of more complex alloys are the following: for application at temperatures up to 300 C (570 F) the 3 Mo, 6 Al and 4 Al alloys; and for application at temperatures approximately 425 to 550 C (800 to 1020 F) the 6 Al alloy.

    Creep-rupture testing was done on the following ternary alloys: 6 Al, 0.04 B; 6 Al, 0.5 Be; 6 Al, 6 Cr; 6 Al, 6 Fe; 6 Al, 6 Mn; 5 Al, 5 Mo; 6 Al, 4 Mo; 6 Al, 6 Mo; and 6 Al, 10 Mo; 7 Al, 3 Mo; 8 Al, 4 Mo; 8 Al, 6 Mo; 6 Al, 0.3 Si; 6 Al, 0.5 Si; and 6 Al, 1 Si; 7 Al, 0.5 Si; 8 Al, 1 Si; 5 Al, 2.5 Sn; 5 Al, 5 Sn; 6 Al, 1 Ta; 6 Al, 3 Ta; and 6 Al, 5 Ta; 8 Al, 1 Ta; 8 Al, 3 Ta; and 8 Al, 5 Ta; 6 Al, 2 V; 6 Al, 4 V; 8 Al, 2 V; 8 Al, 4 V; 6 Al, 4 Zr; 8 Al, 3 Zr; 3 Mo, 0.5 Si; and 4 V, 0.75 Si. Most of the creep-rupture testing was done at 425 and 550 C (800 and 1020 F), with a few alloys being tested at 300 or 650 C (570 or 1200 F). Also, the effect of additions of carbon, nitrogen, and oxygen on creep-rupture properties was evaluated. Stability data for some alloys are reported. Ternary alloys showing promise for application, and as bases for the development of more complex alloys are: 5 Al, 5 Mo; 6 Al, 4 Mo; 7 Al, 3 Mo; 6 Al, 2 V; and 6 Al, 4 V. Tin and zirconium show promise as complexing additions which improve creep performance without detriment to tensile ductility.

    Quaternary alloys evaluated were of the 6 Al, 3 Mo, X type and 6 Al, 0.5 Si, Y type where X represents additions of 0.04 per cent boron, 0.5 per cent beryllium, 0.3 per cent carbon or 0.5 per cent silicon and Y represents 1 or 2 per cent molybdenum or 4 per cent vanadium.

    The most creep resistant alloy developed having good tensile ductility and stability is the 7 Al, 3 Mo alloy. A limited forging study of this alloy indicated that it can be processed to have excellent combinations of strength and ductility.


    Paper ID: STP44148S

    Committee/Subcommittee: B02.08

    DOI: 10.1520/STP44148S


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