Consequences of asymmetric energy barriers to dislocation motion

Li, J.C.M

doi:10.1016/0001-6160(70)90008-8

Cited by 7 publications

(3 citation statements)

References 23 publications

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“…Following the arguments of Li on dislocation velocity [22], we have, for a reversible crack motion under a zero effective driving force ~d*, a net zero crack velocity:…”

mentioning

confidence: 99%

Thermally activated crack propagation ? theory

Pollet

Burns

1977

Int J Fract

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Steady state crack propagation in solids is analyzed as a thermally activated process. The fracture mechanics concept of a crack driving force is formally introduced to molecular rate theory. This representation of crack propagation appears to be, in many aspects, similar to that of the motion of a dislocation under a shear stress across thermal obstacles. The basic thermodynamic relations are derived for steady state crack propagation using assumptions similar to those well accepted in theories of deformation based on thermally activated dislocation motion.

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“…Following the arguments of Li on dislocation velocity [22], we have, for a reversible crack motion under a zero effective driving force ~d*, a net zero crack velocity:…”

mentioning

confidence: 99%

Thermally activated crack propagation ? theory

Pollet

Burns

1977

Int J Fract

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“…По-перше, при пластичній деформації мартерситних кристалів відбувається зниження ступеню тетрагональності їх кристалічної решітки, що за характером впливу є аналогічним пом'якшенню [5]. Обумовлений наведений стан переходом атомів вуглецю з твердого розчину на дислокації, які введені в метал при волочінні [7,11,12].…”

Section: визначений характер зміни 220unclassified

Technology of Making of Armature With High Level of Durability

Вакуленко¹,

Пройдак²,

Proidak³

et al. 2014

bttrp

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Purpose. Assessing the impact of technological parameters on the properties of the complex in the manufacture of valves with a high level of safety. Methodology. Material for the study was selected alloy steel 20ХГС2. Curing rods with a diameter of 6,5 mm was performed rapid cooling from temperatures of 1080…1100 °C. The heating was carried out in Vacation chamber furnaces. Cold plastic deformation was carried out by drawing. Mechanical properties were determined from the analysis of stress-strain curve. The microstructure was studied using light microscopy and methods of quantitative metallographic. The parameter evaluating thin crystalline structure of the metal line width has been used ( ) x-ray interference (220). Findings. Shows the change in the properties of the complex as a function of temperature end of accelerated cooling of steel wire rod, which is being investigated. The analysis of the structural state of rolled after heat strengthening and after various degrees of plastic deformation by drawing. Shown that 20…30 % after deformation rapidly cooled to a temperature of steel 20ХГС2 580…600 °C, elongation is maintained at the level of 6 %, while the strength reaches at values of 2000-2100 MPa. Using the tempering at an intermediate temperature can improve the plastic properties of the pre-heat-strengthened, cold-rolled steel. Originality. The deformation of the thermally bonded low-alloy steel 20ХГС2 accompanied by a monotonic decrease in the line width of x-ray interference (220). Rate of increase in strength during cold deformation of steel martensite-bainite structure is due to the simultaneous development processes from the decay of the softening of martensitic structures and deformation strengthening. Practical value. The research results can be used to develop high-technology manufacturing reinforcing bar in an industrial environment for steel making

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“…The problem of thermal activation of a dislocation over an asymmetric Peierls energy barrier has been analysed thermodynamically by Li (1970) and Nichols (1971) in connection with high-temperature creep ; the t,wo analyses Downloaded by [University of Auckland Library] at 20:13 05 June 2016 easy and hard senses, and t h a t the activation volumes will only be the same a t one value of T* where the curves cross, i.e.…”

Section: Ctivation Volume and Activation Enthalpymentioning

confidence: 99%