The Mechanisms of Fatigue and Fracture of Metal/Ceramic Interfaces

Introduction

Multi-layered and composite systems, which often contain metal/ceramic interfaces, are widely used in industry, both in microelectronic packaging and structural materials. In order to make long-term reliable multi-layered electronic devices and reliable structural composites, the fatigue and fracture behavior of material interfaces needs to be well understood. Thus, the need to understand what governs the mechanical properties of the interfaces between these dissimilar materials becomes important as the mechanical properties of these interfaces ultimately control the reliability of the device.

Background

One model metal/ceramic interface system which has been studied here at Berkeley, Al/Al₂O₃, is also of some practical interest as thin layers of pure aluminum are commonly used in the microelectronics industry as conductors. Previous investigations (Int. J. Fract., 66, 1994, pp. 227 and Acta Mat. 44 1996, pp. 4713) into the fracture and fatigue behavior of these types of interfaces for 99.999% pure aluminum layers, 100 - 500 mm thick, sandwiched between 99.5% pure alumina have shown:

Under monotonic loading cracks tended to grow within or be drawn towards the more compliant aluminum layer, this may be attributed to the elastic modulus mismatch as predicted by linear-elastic theory.

Although nominal (crack initiation) fracture toughness values (using SSY assumptions) were found to be layer thickness independent, after accounting for large scale plastic dissipation, an order of magnitude range of fracture energies was found with stain energy release rates increasing with layer thickness.

Under cyclic loading at moderate to low applied driving forces, cracks tended to grow at the interface with evidence of ductile, striation formation. Growth rates were found to be independent of layer thickness over the range investigated.

Under static loading in lab air no evidence of environmentally assisted slow-crack growth was found.

Continuing Research

Previous results have indicated that plastic dissipation and constraint in the metal layer may be important and effect the fracture and fatigue behavior in a variety of ways. Research continues, on the effect of constraint as metal layer thickness is reduced, in the following areas:

Fracture: As the metal layer becomes on the order of or smaller than the plastic zone size the amount of plastic dissipation in the metal layer will be further reduced. This would be expected to reduce strain energy release rates and crack initiation toughness values (using SSY assumptions), and possibly effect crack path trajectories.

Fatigue: As the metal layer becomes constrained, advancement of cracks by ductile striation formation may be hindered or suppressed. Failure modes other then striation formation may begin to play a role or become prominent.

Stress Corrosion Cracking: It is well documented that environmentally assisted slow-crack growth occurs in alumina under static loading in a moist environment. As the metal layer becomes more constrained, stresses at the crack-tip may become large enough to activate such previously unobserved failure mechanisms in sandwich specimens under both static and cyclic loading.

Furthermore, it is the goal of this research to investigate the fracture and fatigue behavior Al/Al₂O₃ interfaces in sandwich specimens where the thickness of the metal layers are in the range of 1mm - 100mm to further understand the role of constraint in the metal layer.

Current Researchers:

                                J. J. Kruzic
                                R. M. Cannon
                                R. O. Ritchie

Recent Publications:

J. J. Kruzic, J. M. McNaney, R. M. Cannon, and R. O. Ritchie, "Effects of Plastic Constraint on the Cyclic and Static Fatigue Behavior of Metal/Ceramic Layered Structures," Mechanics of Materials, 2003, in press.

J. J. Kruzic, R. A. Marks, M. Yoshiya, A. M. Glaeser, R. M. Cannon, and R. O. Ritchie, "Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium/Copper Interlayers," Journal of the American Ceramic Society, 2002, 85 (10), 2531-2541.

J. J. Kruzic, J. M. McNaney, R. M. Cannon, R. O. Ritchie, "Time Dependent Debonding of Aluminum/Alumina Interfaces Under Cyclic and Static Loading," in Structure-Property Relationships of Oxide Surfaces and Interfaces, MRS Symposium Proceedings, C. B. Carter, X. Pan, K. Sickafus, H. L. Tuller, and T. Wood, eds., Materials Research Society, Warrendale, PA, 2001. p. AA4.10.1-6.

Publications of the Ritchie Group on the Fatigue and Fracture of Bimaterial Interfaces

Tae Sung Oh, R. M. Cannon, and R. O. Ritchie, "Subcritical Crack Growth along Ceramic-Metal Interfaces," Journal of American Ceramic Society, vol. 70 (12), Dec. 1987, pp. C352-355.
T. S. Oh, R. M. Cannon, J. Rödel, A. M. Glaeser, and R. O. Ritchie, Effects of Near Interfacial Microstructures on Toughness and Subcritical Crack Growth in Ceramic/Metal Systems," in Interfaces in Polymers, Ceramics, and Metal-Matrix Composites, Proceedings of the Second International Conference on Composites Interfaces (ICCI- II), H. Ishida, ed., Elsevier Science, New York, NY, 1988, pp. 567- 581.
Tae Sung Oh, J. Rödel, R. M. Cannon, and R. O. Ritchie, "Ceramic/Metal Interfacial Crack Growth: Toughening by Controlled Microcracks and Interfacial Geometries," Acta Metallurgica, vol. 36 (8), August 1988, pp. 2083-2093.
T. S. Oh, R. M. Cannon, and R. O. Ritchie, "On Optimizing the Toughening of Ceramic/Metal Interfaces using Implanted Microcracks," in Metal-Ceramic Joints, MRS International Meeting on Advanced Materials, Proceedings, N. Iwamoto and T. Suga, eds., Materials Research Society, Pittsburgh, PA, vol. 8, 1989, pp. 105-112.
T. S. Oh, R. M. Cannon, and R. O. Ritchie, "Tailored Microstructures to Control Interfacial Toughness," in Thin Films: Stresses and Mechanical Properties, MRS Symposium Proceedings, J. C. Bravman, W. D. Nix, D. M. Barnett, and D. A. Smith, eds., Materials Research Society, Pittsburgh, PA, vol. 130, 1989, pp. 219-224.
R. M. Cannon, B. J. Dalgleish, R. H. Dauskardt, T. S. Oh, and R. O. Ritchie, "Cyclic Fatigue-Crack Propagation along Ceramic/Metal Interfaces," Acta Metallurgica et Materialia, vol. 39 (9), Sept. 1991, pp. 2145-2156.
R. M. Cannon, B. J. Dalgleish, R. H. Dauskardt, R. M. Fisher, T. S. Oh, and R. O. Ritchie, "Ceramic/Metal Interfaces: Monotonic and Cyclic Fatigue Resistance," in Fatigue of Advanced Materials, R. O. Ritchie, R. H. Dauskardt and B. N. Cox, eds., MCEP Ltd., Edgbaston, U.K., 1991, pp. 459-482.
R. O. Ritchie, R. M. Cannon, B. J. Dalgleish, R. H. Dauskardt, and J. M. McNaney, "Mechanics and Mechanisms of Crack Growth at or Near Ceramic-Metal Interfaces: Interface Engineering Strategies for Promoting Toughness," Materials Science and Engineering A, vol. A166, 1993, pp. 221-235.
J. C. Card, R. M. Cannon, R. H. Dauskardt, and R. O. Ritchie, "Stress-Corrosion Cracking at Ceramic-Metal Interfaces," in Joining and Adhesion of Advanced Inorganic Materials, MRS Symposium Proceedings, A. H. Carim, D. S. Schwartz, and R. S. Silberglitt, eds., vol. 314, Materials Research Society, Pittsburgh, PA, 1993, pp. 109-116.
R. O. Ritchie, R. M. Cannon, B. J. Dalgleish, R. H. Dauskardt, and J. M. McNaney, "On the Strength and Toughness of Structural Ceramics Bonded to Metals," Transactions of the Materials Research Society of Japan, vol. 14A, Dec. 1994, pp. 409-412.
J. M. McNaney, R. M. Cannon and R. O. Ritchie, "Near-Interfacial Crack Trajectories in Metal-Ceramic Layered Structures," International Journal of Fracture, vol. 66, 1994, pp. 227-240.
B. J. Dalgleish, E. Saiz, A. P. Tomsia, R. M. Cannon, and R. O. Ritchie, "Interface Formation and Strength in Ceramic-Metal Systems," Scripta Metallurgica et Materialia, vol. 31 (8), 1994, pp. 1109-1114.
J. M. McNaney, R. M. Cannon and R. O. Ritchie, "Elastic Compliance of Four-Point Bend Samples Comprising Two Linear-Elastic Materials Bonded with a Thin Layer," ASTM Journal of Testing and Evaluation, vol. 23 (2), March 1995, pp. 95-101.
R. O. Ritchie, "Crack Propagation in Metal-Matrix Composites. I: Interaction of Cracks with Metal/Ceramic Interfaces", in Mechanical Behavior of Materials at High Temperatures, C. Moura Branco, R. O. Ritchie, and V. Sklenicka, eds., Kluwer, Dordrecht, The Netherlands, 1996, pp. 445-460.
R. O. Ritchie, "On the Interaction of Cracks with Bimaterial Interfaces," Physiochemical Mechanics of Materials, vol. 32 (1), 1996, pp. 119-132.
J. M. McNaney, R. M. Cannon and R. O. Ritchie, "Fracture and Fatigue-Crack Growth along Aluminum/Alumina Interfaces," Acta Materialia, vol. 44 (12), Dec. 1996, pp. 4713-4728.
J. M. McNaney, R. Havens, and R. O. Ritchie, "Elastic Compliance of the Compact-Tension Specimen Comprising Two Linear-Elastic Materials Bonded with a Thin Layer," ASTM Journal of Testing and Evaluation, vol. 25 (1), Jan. 1997, pp. 28-35.
T. L. Becker, Jr., J. M. McNaney, R. M. Cannon and R. O. Ritchie, "Limitations on the Use of the Mixed-Mode Delaminating Beam Test Specimen: Effect of the Size of the Region of K-Dominance," Mechanics of Materials, vol. 25, 1997, pp. 291-308.
T. L. Becker, Jr., J. M. McNaney, R. M. Cannon and R. O. Ritchie, "Effects of the Limited Region of K-Dominance in the Mixed-Mode Delaminating Beam Test Specimen," Ceramic Transactions, vol. 77, 1997, pp. 149-156.
J. M. McNaney, R. M. Cannon and R. O. Ritchie, "Effects of Plasticity on the Toughness and Fatigue Crack Propagation of Metal/Ceramic Interfaces, "Ceramic Transactions, vol. 77, 1997, pp. 157-164.
R. O. Ritchie, R. M. Cannon, J. M. McNaney, and J. C. Card, "On the Structural Integrity of Metal-Joined Ceramics," Proceedings of the 9th CIMTEC-World Ceamics Congress and Forum on New Materials (Florence, June 14-19, 1998), P. Vincenzini, ed., 1998.
J. M. McNaney, R. M. Cannon, R. O. Ritchie, and P. Papadoupoulos, "Statistical Aspects of the Strength and Toughness of Metal-Ceramic Interfaces," Proceedings of the 9th CIMTEC-World Ceramics Congress and Forum on New Materials (Florence, June 14-19, 1998), P. Vincenzini, ed., 1998.
J. J. Kruzic, J. M. McNaney, R. M. Cannon, R. O. Ritchie, "Time Dependent Debonding of Aluminum/Alumina Interfaces Under Cyclic and Static Loading," in Structure-Property Relationships of Oxide Surfaces and Interfaces, C. B. Carter, X. Pan, K. Sickafus, H. L. Tuller, and T. Wood, eds., MRS Symposium Proceedings, vol. 654, Materials Research Society, Warrendale, PA, 2001. p. AA4.10.1-6.
J. J. Kruzic, R. A. Marks, M. Yoshiya, A. M. Glaeser, R. M. Cannon, and R. O. Ritchie, "Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium/Copper Interlayers," Journal of the American Ceramic Society, 2002, 85 (10), 2531-2541.
J. J. Kruzic, J. M. McNaney, R. M. Cannon, and R. O. Ritchie, "Effects of Plastic Constraint on the Cyclic and Static Fatigue Behavior of Metal/Ceramic Layered Structures," Mechanics of Materials, 2003, in press.

LBNL, MSD * Ritchie Group * Dept. of MSME, UC Berkeley