摘要:

AbstractThe effect of temperature and strain rate on the 0·2% yield strength, ultimate tensile strength, and percentage elongation of M250 maraging steel was investigated under uniaxial tensile conditions in the temperature range from 25 (room temperature) to 550°C and strain rate range 10−4–10−1S−l. Up to 400°C the steel shows essentially strain rate insensitive behaviour with a gradual decrease in the 0·2% yield strength and ultimate tensile strength. The elongation remains constant at all strain rates up to 300°C. Fractographic analysis indicates that the increasing strain rate induces strain constraint resulting in an increased dimple size. An elongated structure was observed at temperatures above 400°C. X-ray diffraction reveals the presence of reverted austenite in the specimens tested at 550°C.MST/3263

ISSN:0267-0836    

DOI:10.1179/mst.1996.12.7.607

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractMetallographic observations have in the past demonstrated conclusively that the bainite transformation is susceptible to mechanical stabilisation. This means that the growth of bainite can be hindered when the transformation occurs in austenite which is plastically deformed, although the rate of heterogeneous nucleation may be accelerated. In the present work we report dilatometric measurements to confirm the earlier metallographic observations and include an interpretation of the effect of prestrain on the martensite thatformsfrom the carbon enriched residual austenite that remains after bainite.MST/3616

ISSN:0267-0836    

DOI:10.1179/mst.1996.12.7.610

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractReorientation towards a〈110〉fibre texture by the submicrometre unrecrystallised grains of the mechanically alloyed nickel based superalloy MA6000 has been observed behind the secondary recrystallisation interface during the zone annealing process. The driving force is considered to be the potential reduction in grain boundary energy, and possible mechanisms are those of grain rotation or the preferential growth of suitably oriented annealing twins. From orientation analyses by microbeam electron diffraction it is demonstrated that the reorientation arises from the latter process.MST/3615

ISSN:0267-0836    

DOI:10.1179/mst.1996.12.7.613

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor