丛林 发表于 2025-3-26 21:44:55
Stress Cycles,. Thermal cycles induce low cycle fatigue in material and stresses arise from the difference in the thermal expansion coefficients and repeated shut down and reopen of the service temperature. Several empirical relations have been suggested for low cycle fatigue such as Morrow‘s and Coffin—Manson CoInsulin 发表于 2025-3-27 04:38:57
Fatigue Life,les a material can withstand before failure. Damage is induced in a component by crack initiation and propagation and their combination determines the total fatigue life. Cycles to failure in alumina SiC composite and yttria stabilized zirconia were applied for the determination of the fatigue limitbarium-study 发表于 2025-3-27 07:28:54
Strengthening (Softening), beyond the yield point. An increasing stress is required to produce additional plastic deformation and the metal apparently becomes stronger and more difficult to deform. Dislocation activity is associated with hardening via pinning and hindering their motion. Grain boundaries are obstacles to dislectropion 发表于 2025-3-27 11:19:46
http://reply.papertrans.cn/25/2420/241978/241978_34.pngInfuriate 发表于 2025-3-27 15:36:37
http://reply.papertrans.cn/25/2420/241978/241978_35.pngOverdose 发表于 2025-3-27 18:09:26
Structural Observations in Fatigued Specimens,process starts with dislocation movements at the microscopic level forming persistent slip bands which become the nucleus of short cracks. The fatigue fracture occurs at three stages, namely (I) initiation, (II) propagation and (III) final rupture. The structural damage in components can occur in stbizarre 发表于 2025-3-28 02:01:28
Work Hardening (Softening),rain boundaries or twin boundaries which hinder dislocation motion can harden the ceramic. The stress amplitude at which failure occurs for a given number of cycles is known as the fatigue strength, and the number of cycles required for a material to fail at a certain stress range is its fatigue lif不规则 发表于 2025-3-28 05:30:25
Fatigue Fracture,ue cracking results from cyclic stresses that are below the ultimate tensile stress, or even the yield stress of the material. Surface flaws small are serving as stress risers where cracks can initiate, leading to fracture under repeated stresses. Porosity is detrimental to fatigue resistance and ad贫穷地活 发表于 2025-3-28 09:29:11
http://reply.papertrans.cn/25/2420/241978/241978_39.png哎呦 发表于 2025-3-28 11:06:51
The Effect of Environment,thus more pronounced. Whatever the environment might be, liquid or gaseous, its effect generally is a reduction in fatigue life. The liquid environments are: water, seawater, liquid metals; those of gases are: hydrogen, water vapor (steam), helium, oxygen and air. Vacuum should also be considered as