High-temperature creep-deformation behavior of the Ni-based superalloy M963
- PDF / 631,391 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 109 Downloads / 163 Views
I. INTRODUCTION
NI-BASED superalloys are mainly strengthened by precipitates and solution additions and are produced in various forms suitable for application at high temperature, due to their excellent creep and fatigue strength and good corrosion resistance. At high temperature, the life of turbine blades and vanes is controlled by creep deformation and damage processes of the materials.[1] Extensive research has been focused on investigating the creep behavior of some commercial Ni-based superalloys, including the effects of minor elements (such as C, B, and Zr),[2,3,4] the environment,[5,6,7] -rafting,[8–12] dislocation structures,[13–18] creep-fatigue behavior,[19,20,21] etc. The M963 alloy, a polycrystalline Ni-based superalloy, is being used as a material for blades and vanes in gas-turbine engines. It has a chemical composition and microstructure similar to those of the Ni-based superalloy Mar-M200. Due to its relatively high contents of refractory elements such as tungsten, molybdenum, titanium, niobium, etc., it has been reported that the alloy has intermediate-temperature brittleness,[22] and some efforts have been made to improve this behavior.[23,24] Investigating the creep-deformation mechanism can benefit the efforts to develop high-temperature alloys, to achieve more-resistant alloys, and to rationalize the creep behavior of these alloys. Until now, the high-temperature creep properties of the M963 superalloy have not been published. The purpose of the present work is to explore in detail the creep behavior under constant load at different temperatures and stresses and to gain a deeper understanding of the high-temperature creep-deformation mechanisms of the M963 superalloy. II. EXPERIMENTAL PROCEDURE The chemical composition of the M963 alloy used in this work is given in Table I. The minor elements are 8 wt ppm P, 10 wt ppm S, 3 wt ppm O, and 6 wt ppm N. The L.Z. HE, formerly Postdoctoral Student, with the Institute of Metal Research, Chinese Academy of Sciences, is Visiting Fellow, Mechanical Engineering Department, University of Wollongong. Contact e-mail: [email protected] Q. ZHENG, Senior Engineer, X.F. SUN and H.R. GUAN, Professors, and Z.Q. HU, Professor and Member of Chinese Engineering Academy, are with the Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, People’s Republic of China. A.K. TIEU, Professor, and C. LU and H.T. ZHU, Research Fellows, are with Mechanical Engineering Department, University of Wollongong, Wollongong, NSW2522, Australia. Manuscript submitted January 4, 2005. METALLURGICAL AND MATERIALS TRANSACTIONS A
master alloy was remelted and cast into test bars, which were then solution treated at 1210 °C for 4 hours, followed by air cooling. The solution-treated microstructure consists of a matrix, precipitate, eutectic, and MC and M6C carbides. The particles at dendrite cores have an average size of 0.1 m and volume fraction of 42 pct, approximately. Creep specimens were machined from solution-treated bars measuring 10 mm in diame
Data Loading...
