scholarly journals Enhanced MALDI ionization efficiency at the metal-matrix interface: Practical and mechanistic consequences of sample thickness and preparation method

2006 ◽  
Vol 17 (5) ◽  
pp. 737-745 ◽  
Author(s):  
Gregor McCombie ◽  
Richard Knochenmuss
Keyword(s):  
Metal Matrix ◽  
Preparation Method ◽  
Sample Thickness ◽  
Ionization Efficiency ◽  
Matrix Interface ◽  
Maldi Ionization

Structure and behavior of metal/ceramic interfaces in Ti alloy/SiC metal matrix composites

1993 ◽  
Vol 8 (5) ◽  
pp. 1158-1168 ◽  
Author(s):  
Ernest L. Hall ◽  
Ann M. Ritter
Keyword(s):  
Metal Matrix Composites ◽  
Reaction Zone ◽  
Metal Matrix ◽  
Ti Alloy ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Fiber Coating ◽  
Sic Particles ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

The structure and mechanical behavior of the fiber/matrix interface in Ti alloy/SCS-6 SiC metal matrix composites were studied. In these composites the interface region consists of a fiber-coating region and a metal reaction zone between the SiC fiber body and the metal matrix. The fiber coating consists of a number of zones or layers which are comprised of cubic SiC particles in a turbostratic carbon matrix. Some ambiguity remains, concerning the number of distinct layers and the size, shape, and density of the SiC particles. The effect of composite fabrication and heat treatment on the coating structure is relatively small. Studies of the metal reaction zone adjacent to the fiber in Ti alloy/SCS-6 SiC MMC's have shown that a number of discrete zones or layers form. Nearest the fiber, a zone of cubic TiC occurs, with increasing grain size with distance from the fiber. Nearest the metal matrix, a zone of Ti5Si3 forms. In high Al content alloys, an intermediate zone forms that consists of Ti2AlC or Ti3AlC. The fiber/matrix interface plays an important role during transverse tensile loading of these composites. The tensile behavior is controlled by debonding at the interface, followed by deformation of the matrix ligaments. Replica observations show that the debonding initiates and propagates within the coating layers, but is not confined to a single layer interface.

Thermally induced dislocation generation in Al/Al2O3 metal-matrix composites

1991 ◽  
Vol 49 ◽  
pp. 588-589
Author(s):  
Kenneth S. Vecchio
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Internal Stresses ◽  
Frictional Stress ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Dislocation Loops ◽  
Thermally Induced ◽  
The Matrix ◽  
Induced Dislocation

It has been well documented that when a large difference in the coefficients of thermal expansion (CTE) exist between the matrix and reinforcement in metal-matrix composites (MMCs) internal stresses can develop which are sufficiently high to generate dislocations at the reinforcement/matrix interface. Numerous observations have been made of this phenomenon via TEM which have shown a variety of different dislocation substructures and dislocation punching mechanisms. An important consequence of this phenomenon is that the metal matrix becomes strain hardened as the dislocation density increases, thereby reducing subsequent plastic flow of the matrix. One notable feature of the dislocation punching mechanism is that prismatic dislocation loops are commonly observed emanating from the interface. In two recent studies it was found that dislocations were not emitted immediately upon cooling, but rather at some lower critical temperature. A number of microstructural and processing parameters can affect the thermally-induced dislocation substructure such as: a) differences in CTEs, b) lattice frictional stress, c) vol.% particulate, d) particle/matrix interface morphology, e) quench temperatures (ΔT effect), and f) thermal-cycling (e.g. reheating and requenching).

THE STRESS ANALYSIS AND THE CRACK BEHAVIOR ACCORDING TO THE CHARACTERISTIC OF THE INTERFACIAL REGION IN FIBER REINFORCED MMC

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4457-4462 ◽  
Author(s):  
OH-HEON KWON ◽  
JI-WOONG KANG
Keyword(s):  
Thin Layer ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Fiber Reinforced ◽  
Elastic Plastic ◽  
High Stiffness ◽  
Crack Behavior ◽  
Fiber Matrix Interface

High performance composite reinforced with unidirectional continuous fibers are used in applications requiring high stiffness, high strength and light weight. Because of the high stiffness of the reinforced continuous fiber, the longitudinal performance of such unidirectional composites is greatly enhanced, but their transverse performance is so weak. The nature of the fiber/matrix interface is one of the important factors which determine the unique properties of the fiber reinforced metal matrix composites (MMCs). So, the current study is focused on the fracture behavior of the interface. Both stress state of the interface and crack parameters of the perpendicular crack to the interface for unidirectional fiber reinforced metal matrix composites under the transverse loading are investigated by using elastic-plastic finite element analysis. Different fiber volume fractions (5~60%) and arrangement (square and hexagon) of fibers were studied numerically. The fiber/matrix interface was treated as multi thin layer with different material properties. The fiber is assumed as linear elastic SiC and the matrix is assumed as elastic-plastic Ti -15-3 Titanium alloy. The results show that the stress distributions of the multi thin layer model have much less changes compared with a single interface case. And the properties of the interfacial zone affect the stress distribution, crack behavior and mechanical behavior of the fiber reinforced metal matrix composite.

Graded Microstructure at Fiber / Copper Matrix Interface in FRM Fabricated by the Reaction at Narrow Holes Method

2005 ◽  
Vol 492-493 ◽  
pp. 737-742 ◽  
Author(s):  
Yasuhiko Tanaka ◽  
Takeshi Goto ◽  
Yoshimi Watanabe
Keyword(s):  
Intermetallic Compound ◽  
Metal Matrix ◽  
Pure Aluminum ◽  
Pure Copper ◽  
High Hardness ◽  
Copper Matrix ◽  
Matrix Interface ◽  
Fiber Metal ◽  
Copper Aluminum ◽  
Aluminum Fiber

The reaction at narrow holes method (RANH method) has been proposed for fabricating fiber reinforced metal (FRM), such as an intermetallic compound fiber / metal matrix composite. This study clarifies a microstructure at a fiber / metal matrix interface of FRM fabricated by using a combination of pure-copper and pure-aluminum in the RANH method. Pure-aluminum fiber was inserted into a narrow hole drilled in the copper matrix. The assembly comprising the pure-aluminum fiber and the pure-copper matrix was heated to a temperature greater than eutectic temperature of the copper-aluminum binary alloy. A molten aluminum reacted with copper to form an annular reacted region consisting of g1 intermetallic compound in a single phase near the edge of the narrow hole. The g1 intermetallic compound has very high hardness on the order of 800-900 HV. The annular reacted region may have a high tensile strength and may work as a reinforcing metal fiber in FRM.

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