摘要:

SUMMARYRecrystallization and recovery have been studied in the high voltage electron microscope (HVEM) in pure copper and two copper‐phosphorus alloys following heavy rolling deformation. Prior to the nucleation of recrystallized grains, extensive subgrain growth occurs by sub‐boundary migration. In the alloys, the first recrystallized grains are observed to nucleate within deformed matrix regions of the same orientation. The orientations of these grains are in close agreement with the crystallographic texture of the metal at complete recrystallization. Growth selection of orientation does not appear to be important. In pure copper, cube‐oriented recrystallized grains form after those of some other orientations, but grow more rapidly and absorb these during g

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03776.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYIn situ tensile straining was carried out in the 1 million volt electron microscope in an attempt to clarify the mechanism(s) of superplasticity in the Zn/Al eutectoid alloy. The dynamic microstructural observations in the 1 MV microscope at 100°C at anmvalue of ∼0.3 were consistent with 100 kV observations of specimens thinned from the bulk and showed that under the experimental conditions used, the predominant mechanism is diffusion of the zinc‐rich (β) phase. It has been theoretically predicted by Lifshitz that diffusional creep and grain‐boundary sliding are inseparable. This is verified by these in situ obser

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03777.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe mechanisms of dissolution of cementite particles in steel have been studied in situ by high voltage electron microscopy. This method permits direct, continuous observations of the process and provides new information which has not been obtained without this technique. During dissolution of cementite particles in austenite at about 770°C, dislocation helices, loops and complex dislocation configurations are formed from the interfaces of the particles. Dissolution of cementite in ferrite during decarburization at about 700°C also causes the formation and movement of dislocations. However, in contrast to the case of dissolution in austenite, the emission of dislocation loops and helices has not been observed. The migration of crystallographic and noncrystallographic interfaces has been observed during the ferrite to austenite transformation. The noncrystallographic interface is apparently attracted to the cementite particles. The migration rate of the noncrystallographic interfaces is five to ten times faster than that of the crystallographic interfac

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03778.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYA gas reaction cell developed for the AEI EM7 has been used to observe directly the structural changes which occur when tantalum is heated in nitrogen. It is demonstrated that sharp images of the microstructure can be obtained from specimens at temperature while surrounded by a 5.5 mm thick layer of the reaction gas at a pressure of 35 torr. The usefulness of the in situ technique for studying gas/metal reactions is assessed.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03779.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe cellular precipitation occurring in an Al–28at%Zn alloy has been followed in situ using a hot stage in the high voltage electron microscope. The cellular reaction starts at grain boundaries and after a period of accelerated growth, a linear growth rate is established. The interlamellar spacing and the rate of growth vary as a function of temperature and the results have been analysed on the basis of the Turnbull theory of cellular precipitation which suggests that the cell boundary diffusion is the rate controlling factor in this syste

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03780.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03781.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY