A Study On Microstructures Of Cold Deformed And Aged Gh4169(inconel718)alloy

ABSTRACT The effect of cold rolling and aging on the morphology and size of y?y攑hase and 6 phase has been studied by the metallographic microscope and the transmission electron microscope in GH4 I 69(lnconel7 18) alloy. The results prove that the 6 phase precipitates first at grain boundary, and then at the deformation bands as cold rolling reduction increases. The shape of 8 phase changes gradually from needle to spheroid as cold rolling reduction increases.The morphology of y拁 y?phases is disc or lens-like ,the size of y拁 y 損hases reduces as cold rolling reduction increases. In this thesis the weight percentage of y拁 y?phases and 8 phase in GH4169 were studied by a method of anode selective potentiostatic electrolysis isolation under different treatments for the first time,it is concluded that the ratio of percentage of y抋nd y攑hase under different treatments, their ratio is about 1:3. The weight percentages of y?, y攁nd 6 phases were determined with a method of quantitative phase analysis by the X-ray diffraction technology under different cold rolling reductions. The results show that the contents of y拁 y攁nd 8 phases increase with cold rolling reduction and aging temperature increasing; By comparing of different passes of cold rolling, the results show that the second pass improve the contents of 6 phase as cold rolling reduction increases; But the amount of y抋nd y攑hase decreases through the second pass cold rolling, then the cold rolling reduction has no great influence on the content of y抋nd y攑hase. The microstructure with a uniform distribution of fine grains.ASTMS梔Oin size and a less amount of 6 phase precipitate along the grain boundary in spheroid or not continual lath-like which were obtained from the process of (DA).At the treatment of 72OI8h0C+620擟/8h,the amount of 8 phase was minimal.