EFFECT OF SALTS ON CREEP BEHAVIOUR OF Ni-BASE ALLOY GH37
CAO Mingzhou QIN Rongshi ZHAO Jixiang (Institute of Metal Research.Academia Sinica.Shenyang)
Cite this article:
CAO Mingzhou QIN Rongshi ZHAO Jixiang (Institute of Metal Research.Academia Sinica.Shenyang). EFFECT OF SALTS ON CREEP BEHAVIOUR OF Ni-BASE ALLOY GH37. Acta Metall Sin, 1987, 23(1): 70-75.
Abstract The creep fracture behaviour of Ni-base alloy GH37 sustained under various loads was studied in three salt depositions:Na_2SO_4,10% NaCl+90% Na_2SO_4 or 20% NaCl+80% Na_2SO_4 at 750—850℃.No remarkable attack was observed in either Na_2SO_4 or 10% NaCl+90% Na_2SO_4,but a violent reduction in life of creep rupture and in creep elongation was expected while in 20% NaCl+80% Na_2SO_4 deposited at rate up to 3 mg/cm~2.The deposition of mixed salts 20% NaCl+80% Na_2SO_4 may destroy the protective oxide film on the alloy surface,meanwhile, may also erode evenly both surface and grain boundaries,and a Cr-depleted layer and intergrartular crackings under stress may be resulted.Therefore,the period of second stage creep is much shortened by interaction of the intergranular crack- ing at surface layer together with internal creep,and the alloy fails prematurely.
