www.melanexjou.fora.pl

[loiwtjsf]

Die Cast Mg-7Al-0.5Y alloy, low cycle fatigue behavior


Strain behavior of the material reflected in the low cycle fatigue loading conditions, the true stress-strain behavior, which can usually be cyclic stress-strain curve 2O2 said. The cyclic stress-strain relations between the exponential law can be expressed as follows: Aa / 2 a K (Ae. / 2) (3) where,[link widoczny dla zalogowanych], Aa / 2 for the cyclic stress amplitude; K for the cyclic strength coefficient; for loop strain hardening index. Figure 3 shows a die-casting Mg alloy 7A1-0.5Y cyclic stress-strain curve, where Aa / 2, and △ e / 2 by the half-life of the stress-strain hysteresis loop obtained. On the experimental data in Figure 3 the linear regression analysis,[link widoczny dla zalogowanych], can according to equation (3) to determine the K and the two calculated values of specific parameters in Table 1. Buttercup = Pi Nan Xin term pregnancy the amount of Ig (3.54x10) 5 × 10 ~ Ig (7.o? XlO groan) lgl0-z strain amplitude (m · m-1) in Figure 3 the logarithm of a 7A1 Die Cast Mg -0.5Y alloy cyclic stress-strain hysteresis curve of Figure 2.4 Cycle 4 Die Cast Mg-7A1-0.5Y alloy at different applied total strain amplitudes of typical hysteresis loop, the hysteresis loop lines are based on test data when the half-life plot of. Can be seen from Figure 4, when the applied total strain amplitude △ e/2-0.9%, the Die Cast Mg through a 7A1-0.5Y alloy /. '. / T (a) △ £ / 2-0.9 %//// l /. / T (b) △ E / z a 0.5% u ///,, ● (c) △ El / 2 = 0.4% (d) △ E / z = 0.3% Figure 4 Die Cast Mg-7Al-O. 5Y homes gold in different applied total strain amplitude hysteresis cycle under the hysteresis loop tensile and compressive deformation occurred jagged ups and downs are part of the phenomenon (see Figure 4a,[link widoczny dla zalogowanych], arrow), this phenomenon usually jagged ups and downs be considered during material deformation due to dynamic strain aging rg]. It is actually material in plastic deformation process, the diffusion of solute atoms and the movement caused by the interaction between dislocations. Solute atoms and the interaction between dislocations,[link widoczny dla zalogowanych], in order to reduce the energy, solute atoms tend to gather around the wrong place,[link widoczny dla zalogowanych], the formation of solute atoms of air. The state of the solute Mg casting alloy of a 7AI a 0.5Y low cycle fatigue behavior of Li Feng Shi Jiatuo atomic air mass on dislocation drag. Impede the movement of dislocations when the stress is increased to overcome this drag force, the movement of dislocations will suddenly break free of solute atoms of air. Again until the movement spread of the dislocation re-pinning of solute atoms repeated this process to result in loop hysteresis phenomenon of online appear jagged ups and downs, however, when the applied total strain amplitude △ E Tuo to c}. . %, 0.4% and 0.5%. Die Cast Mg 0.5Y together a box of a 7AI cycle hysteresis phenomenon did not appear jagged ups and downs. Indicate a lower total strain amplitudes applied. Fatigue does not occur during the dynamic deformation effects payable H In fact, during the low cycle fatigue deformation, only when the movement of dislocations when the density reaches a certain magnitude. It may appear the phenomenon of serrated yielding. The total strain-controlled fatigue loading conditions. Completion of the week loop-like movement of deformation of the need to generate the dislocation density and the applied total strain is closely related to the level of increase. General. The larger the total strain amplitude applied. Deformation in a week cycles required during the movement of the dislocation density produced larger clear that in order to produce the required movement serrated yielding dislocation density, plus the total strain amplitude must exceed a certain threshold, which is applied only when the total strain 0.9% increase was observed when the dynamic aging phenomenon is due to direct change of 2.5 to determine the fatigue fracture morphology under low-cycle fatigue loading in the cast magnesium Taijin fatigue crack initiation and growth patterns. By scanning electron microscopy (SEM) for low cycle fatigue fracture specimens were observed fracture surface was found. Die Cast Mg a 7A10.5Y Taijin. In the low cycle fatigue loading, crack initiation at the specimen surface near the table I loose or mixed with other casting defects (Figure j) (a) fatigue crack initiation near the surface of bore sparse Awake t | 1) plague workers Frog snapped suspected surface near the central initiation complex site. AE | 2-06j% △ -2 = 0.8% Figure 5 Die Chi M7A10, 5Y gangrene base station Wei Kuang Lo split the micro view of mosquito (Po Tau referred to at the fatigue source) Figure 6 CAST Mg7A } a 05Y Taijin SEM fatigue crack growth region morphology. Visible. Die Cast Mg a 7A] applied a total 0.5Y Taijin different strain amplitudes are based on the fatigue crack growth transgranular manner. 3 Results-Te (1) Die Cast Mg7A [0.5Y alloy at high strain amplitudes applied showing the total cyclic strain hardening and post-initial cycle stability. In the lower 203

相关的主题文章：


[link widoczny dla zalogowanych]

[link widoczny dla zalogowanych]

[link widoczny dla zalogowanych]