Download or read book Fiber Volume Fraction Effects on Fatigue Response of a SCS 6 Ti 15 3 Metal Matrix Composite at Elevated Temperature written by Sean C. Coghlan and published by . This book was released on 1997-09-01 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study was to determine the effects of fiber volume fraction on the fatigue behavior of Silicon Carbide fiber-reinforced Titanium alloy, SCS-6/Ti-15-3. Three fiber volume fractions were investigated; 15%, 25%, and 42%. The tests were performed under fully-reversed, strain- controlled conditions at 427 C. The primary objectives of this study were to develop a fatigue life diagram and to document the damage and failure mechanisms. Compressive loads on the slender specimens were kept from buckling the specimens through the use of a buckling guide. This device allows unrestricted axial movement of the composite, while preventing any out-of-plane motion. No buckling damage due to compression was found in any of the specimens. Modulus behavior and stress versus strain curves were recorded during cycling for each test. An applied strain range between 0.5% and 1.1% was used for the majority of the tests. This resulted in fatigue lives between approximately 10, 000 and 100,000 cycles. The resulting fatigue life diagram showed similar life at strain ranges at and above 0.008 mm/mm for all fiber volume fractions. At strain levels below 0.008 mm/mm, there was an increasing fatigue life with increasing fiber volume fraction. The 15% and 42% V sub f material was consolidated with a molybdenum cross-weave to hold the fibers in alignment. The 25% V sub f material had a titanium-niobium cross-weave for the same purpose. The Mo cross-weave was present on every fracture surface of the 15% and 42% V sub f material. This indicated that it was detrimental to the fatigue life of the composite. No cross-weave material was found on the fracture surfaces of the 25% V sub f. Major cause of specimen failure was the initiation and propagation of fatigue cracks in the matrix that were perpendicular to the applied load.

Download or read book Stress strain Ratio Effects on Fatigue Response of a SCS 6 Ti 15 3 Metal Matrix Composite at Elevated Temperature written by Sean C. Jackson and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stress strain Ratio Effects on Fatigue Response of a SCS 6 Ti 15 3 Metal Matrix Composite at Elevated Temperature written by Sean C. Jackson and published by . This book was released on 1995 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Unnotched SCS 6 Ti 15 3 Metal Matrix Composites at 650 C written by and published by . This book was released on 1990 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Fatigue Damage in a Metal Matrix Composite SCS 6 TI 15 3 at Elevated Temperature written by and published by . This book was released on 1993 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fatigue characteristics of a unidirectional titanium based metal matrix composite site (MMC) were investigated at elevated temperature (427 deg C). A hybrid strain controlled loading made was used to subject the 0 deg and 90 deg laminas to fatigue. Along with the fatigue tests, microscopy and analytical modeling were also conducted. This combination of activities led to defining the initiation and progression of damage and deformation in the MMC. When loading was parallel to the fiber direction, the fatigue behavior was initially dominated by creep deformation of the matrix. Then, depending on the maximum strain, specimen failure was the result either fiber fractures or matrix cracking. In contrast, when loading was perpendicular to the fiber direction, the fatigue response was first dominated by the initiation of fiber-matrix interface damage. Then, if the maximum strain was above .35%, the dominant damage mechanism was matrix cracking. Below this strain level, the damage was a mixture of matrix microcracks and the progression of fiber-matrix interface damage. The analysis for this fiber orientation included unique methods to model the interface damage. This hybrid approach involving experiments, microscopy, and analytical modeling provided better understanding of the fatigue behavior of the MCC.

Download or read book A Study of Fiber Volume Fraction Effects in Notched Unidirectional SCS 6 Ti 15V 3Cr 3Al 3Sn Composite written by Steven J. Covey and published by . This book was released on 1993 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Unnotched SCS 6 Ti 15 3 Metal Matrix Composites at 650 C written by WS. Johnson and published by . This book was released on 1992 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: TI-15-3 reinforced with SCS-6 silicon carbide fibers, in five different lay-ups, was tested at 650°C to determine monotonic and fatigue strengths, basic mechanical properties, and damage initiation and progression. The elevated temperature results were compared to those obtained at room temperature. Analytical predictions were made of the monotonic stress-strain response as well as cyclic stress-strain hysteresis. The fiber reinforcement was found to increase significantly the static and fatigue strengths of the laminates over those of the matrix material at elevated temperature; the increase was insignificant at room temperature. Initial damage, in either the fibers or the matrix, was partitioned as a function of the life and applied strain range in the constituents. High strains and short lives resulted in multiple fiber failure with no signs of matrix fatigue cracking. Low strains and long lives resulted in extensive matrix cracking and no fiber breaks away from the fracture surface. At 650°C, the matrix was too weak to cause fiber-matrix interface failure before matrix yielding. Laminate fatigue lives were hypothesized to be a function of the 0° fiber stress. More scatter was found in the 0° fiber stress versus high temperature fatigue life data than in the room temperature data. An initial unloading modulus that was greater than the initial loading modulus was observed in the elevated temperature fatigue tests.

Download or read book Isothermal Fatigue Mechanisms in Ti based Metal Matrix Composites written by Bhaskar S. Majumdar and published by . This book was released on 1993 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stress-controlled isothermal fatigue experiments were performed at room temperature (RT) and 548 C (in argon) on (0)8 SCS6/Ti 15-3 metal matrix composites (MMC's) with 15 and 41 volume percent SCS6 (SiC) fibers. The primary objectives were to evaluate the mechanical responses, and to obtain a clear understanding of the damage mechanisms leading to failure of the MMC's. The mechanical data indicated that strain ranges attained fairly constant values in the stress-controlled experiments at both RT and 538 C, and remained so for more than 85 percent of life. The fatigue data for MMC's with different volume fraction fibers showed that MMC life was controlled by the imposed strain range rather than the stress range. At RT, and at low and intermediate strain ranges, the dominant fatigue mechanism was matrix fatigue, and this was confirmed metallurgically from fractographic evidence as well as from observations of channel type dislocation structures in the matrix of fatigued MMC specimens.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Fatigue and Durability of Metals at High Temperatures written by S. S. Manson and published by ASM International. This book was released on 2009 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: From concept to application, this book describes the method of strain-range partitioning for analyzing time-dependent fatigue. Creep (time-dependent) deformation is first introduced for monotonic and cyclic loading. Multiple chapters then discuss strain-range partitioning in details for multi-axial loading conditions and how different loading permutations can lead to different micro-mechanistic effects. Notably, the total-strain method of strain-range partitioning (SRP) is described, which is a methodology that sees use in several industries. Examples from aerospace illustrate applications, and methods for predicting time-dependent metal fatigue are critiqued.

Download or read book Metals Abstracts written by and published by . This book was released on 1998 with total page 1042 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Longitudinal Fatigue Response of a Metal Matrix Composite Under Strain Controlled Mode at Elevated Temperature written by S. Mall and published by . This book was released on 1994 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fatigue characteristics of a unidirectional titanium-based metal matrix composite (MMC) (SCS-6/Ti-15-3) were investigated at elevated temperature (427°C). A hybrid strain controlled loading mode was employed for this purpose. This hybrid control mode did not allow the specimen to experience compressive stress in order to prevent any possible buckling effects. To fully understand the fatigue behavior of the MMC under this control mode, fatigue tests, microscopic evaluation, and micromechanical analysis were performed. Based on this combination of activities, the damage and deformation mechanisms were systematically identified. It was found that the fatigue behavior was initially dominated by creep deformation of the matrix. This was accompanied by plastic deformation in those specimens that were subjected to a maximum strain level of 0.55% or higher. Depending on the maximum strain level, the specimen failure was a result of either fiber fracture or matrix cracking. Using the combined approach involving experiments, microscopy, and analysis, the interrelationships among applied strain levels, fatigue life, damage mechanisms, and macroscopic response were established to characterize the longitudinal fatigue characteristics of the tested MMC.

Download or read book Transverse Fatigue Response of a Metal Matrix Composite Under Strain Controlled Mode at Elevated Temperature written by BP. Sanders and published by . This book was released on 1995 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present paper is a continuation of Part I to investigate the transverse fatigue behavior of a unidirectional titanium-based metal matrix composite (MMC) (SCS-6/Ti-15-3) at elevated temperature. In Part I of this paper, fatigue tests were conducted under the strain-controlled mode, and a systematic microscopic evaluation was undertaken to identify the damage and deformation mechanisms. In this paper (Part II), the fatigue response is modeled using a micromechanical approach where the fiber-matrix interfacial damage is incorporated along with the inelastic behavior of the matrix. The analysis provided additional insight into the transverse fatigue response of the MMC. Combining the results obtained from this micromechanical analysis, and that obtained from the macroscopic response (that is, stress and modulus) and microscopic evaluation in Part I, the transverse fatigue response of the MMC was thoroughly characterized.

Download or read book Characterization of Fatigue Damage in a Metal Matrix Composite SCS 6 TI 15 3 at Elevated Temperature written by Brian P. Sanders (CAPT, USAF.) and published by . This book was released on 1993 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Isothermal Fatigue Mechanisms in Ti Based Metal Matrix Composites written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-08 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stress-controlled isothermal fatigue experiments were performed at room temperature (RT) and 548 C (in argon) on (0)8 SCS6/Ti 15-3 metal matrix composites (MMC's) with 15 and 41 volume percent SCS6 (SiC) fibers. The primary objectives were to evaluate the mechanical responses, and to obtain a clear understanding of the damage mechanisms leading to failure of the MMC's. The mechanical data indicated that strain ranges attained fairly constant values in the stress-controlled experiments at both RT and 538 C, and remained so for more than 85 percent of life. The fatigue data for MMC's with different volume fraction fibers showed that MMC life was controlled by the imposed strain range rather than the stress range. At RT, and at low and intermediate strain ranges, the dominant fatigue mechanism was matrix fatigue, and this was confirmed metallurgically from fractographic evidence as well as from observations of channel type dislocation structures in the matrix of fatigued MMC specimens. Reaction-zone cracks acted as important crack initiating sites at RT, with their role being to facilitate slip band formation and consequent matrix crack initiation through classical fatigue mechanisms. MMC life agreed with matrix life at the lower strain ranges, but was smaller than matrix life at higher strain ranges. Unlike the case of monotonic deformation, debonding damage was another major damage mechanism during fatigue at RT, and it increased for higher strain ranges. At high strain ranges at RT, fractography and metallography showed an absence of matrix cracks, but long lengths of debonds in the outer layers of the SCS6 fibers. Such debonding and consequent rubbing during fatigue is believed to have caused fiber damage and their failure at high strain ranges. Thus, whereas life was matrix dominated at low and intermediate strain ranges, it was fiber dominated at high strain ranges. At 538 C, the mean stain constantly increased (ratchetting) with the number of cycles. At high str...

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1993 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Composites Industry Abstracts written by and published by . This book was released on 1996 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: