Time Dependent Mechanical Behavior of Partially Stabilized Zirconia for Diesel Engine Applications PDF Download

Author: Timothy John Hine
Publisher:
ISBN:
Category : Diesel motor
Languages : en
Pages : 162

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Book Description
The fatigue behavior of several commercially-available MgO partially stabilized zirconias (Mg-PSZ) was studied by measuring the strength as a function of time, temperature, and applied stress level. The two Mg-PSZ types included TS PSZ (thermal shock grade) and MS PSZ (maximum strength/grade/1983 vintage). Both 1983 and 1984 vintages of the TS PSZ (designated TS(83) and TS(84)) were examined. The strength was determined using an interrupted fatigue (I.F.) test in which flexure samples were exposed at temperatures between 500 and 1000C̊ for times up to 1000 h. During testing, the applied stress was maintained at a percentage of the short-term [strength] value measured at the same [temperature]. Specific stress levels included 0, 60, 70, and 80%. The following techniques were used to characterize both the as-received and tested I.F. specimens: (1) SEM, (2) TEM, (3) optical microscopy, (4) x-ray diffraction, (5) micro-Raman spectroscopy, and (6) dilatometry ... The I.F. results indicated that the application of the Mg-PSZ ceramics as high-temperature components should be limited to temperatures of 800C̊ and below particularly when substantial mechanical stresses are involved. Although the strength of the TS and MS PSZ materials tested at 1000C̊ under a no-load condition was relatively insensitive to time, the observed phase instability could lead to mechanical failure in applications involving thermal cycling.