Functional Superelastic Interlayers for Control of Friction and Wear in Hard-Coated Components

This project, funded by NSF under the GOALI program and carried out in collaboration with General Motors Corp., exploits superelastic deformation in sputtered NiTi interlayers, integrated with conventional CrN and DLC hard coatings, to limit substrate damage and reduce contact stresses during dry sliding wear processes. Superelastic interlayers have been observed to improve the performance of hard coatings by more than two orders of magnitude as measured in wear loss studies.

High Temperature Shape Memory Alloy Development for Use above 500 C.

Shape memory alloys such as beta-NiTi can deliver large thermally-driven forces and displace-ments and are potentially useful in a range of aeropropulsion and MEMS actuator applications. Their use is, however, discouraged by a maximum operating temperature of about 100 C. This limitation is surmountable through the use of NiTiX alloys, with X = Hf (substituting for Ti), or Pd, Au or Pt, substitut-ing for nickel on the B2 superlattice. Our recent work on (Ti+Hf)Ni and Ti(Ni+Pd) has shown that good mechanical properties and excellent shape-memory can be obtained in these systems, with austenite-finish temperatures exceeding 240 C. Furthermore, alloys based on TiPt have transformation tempera-tures above 1000 C. Although little is presently known about this material, Ti50Ni20Pt30 should allow design of actuators for operation above 500 C. This NASA-funded project is directed at the development of this class of shape-active metals for application to MEMS, smart composite materials, and high-temperature shape-memory components for turbine engines.

Nitinol Brazing

This project concerns development of a novel joining technique for Nitinol shape-memory and superelastic alloys, recently discovered at MSU in collaboration with John A. Shaw at the University of Michigan Dept. of Aerospace Engineering. Using pure niobium as a melting point depressant, the method produces a highly robust and biocompatible metallurgical bond between NiTi sections. Detailed studies on thermodynamics of the Ni-Ti-Nb ternary system and the kinetics of contact melting in NiTi-Nb couples are underway. Experimental work on the use of the approach in resistance welding, metal-inert gas welding, vacuum brazing, and the joining of sputtered thin films sections are being conducted. A sputtered multilayer brazing foil has been developed which solves long-standing problems associated with metallurgical joining in this important alloy system.

Thin Film Shape Memory Alloys on Polymeric Substrates for Microactuators

This work aims at development of very-low cost microactuator materials using sputtered thin film NiTi alloys as high-energy force-producing elements. The principa objective is to develop methods for web-coating of thin polyimide substrates with NiTi alloys. Deposition of NiTi onto refractory polymers such as DuPont Kapton, aside from allowing low-cost continuous processing of large surface areas, results in a composit film having a number of advantages. Whereas the NiTi shape-memory metallization stiffens and recovers a set shape when heated, the polyimide substrate responds to heating by becoming more compliant, and will tend to recover a set shape when it cools. The materials are thus compatible and highly complimentary, and will form the basis of an important class of extremely rugged microactuation materials capable of providing large forces and smooth displacement output, low-voltage operation, biocompatibility, and the ability to operate in liquids or in harsh environments.

Reviewed Journal Publications

Lagrange, T; Schaublin, R; Grummon, D S; Abromeit, C; Gotthardt, R "Irradiation-induced phase transformation in undeformed and deformed NiTi shape memory thin films by high-energy ion beams" Philosophical Magazine. 85, 577-587 (2005).

Zhang, Y.; Cheng, YT.; Grummon, D.S. "Indentation Stress Dependence of the Temperature Range of Microscopic Superelastic Behavior of Nickel-Titanium Thin Films," J. Appl. Phys. Lett. 98, (2005).

Ni, W.; Cheng, YT.; Lukitsch, M.; Weiner, A.M.; Lev, L.C.; Grummon, D.S. "Novel layered tribological coatings using a superelastic NiTi interlayer," Wear, 259, 842-848, (2005).

Ni, W; Cheng, Y-T; Grummon, D S, "Microscopic shape memory and superelastic effects under complex loading conditions", Surface and Coatings Technology. 177-178, 512-517, (2004).

Vestel, M J; Grummon, D.S. "Precipitates and lamellar microstructures in NiTi films," Materials Science and Engineering. A378, 437-442, (2004).

Vestel, M.J.; Grummon, D.S.; Gronsky, R.; Pisano, A.P. "Effect of temperature on the Devitrification Kinetics of NiTi Films", Acta Materialia 51, 5309-5318, (2003).

Grummon, D.S. "Thin Film Shape-Memory Materials for High-Temperature Applications", J Met. 55, 24-32, (2003).

Ni, W.; Cheng, Y-T.; Grummon, D. S. "Microscopic Behavior of a Nickel-Titanium Alloy Under Complex Loading Conditions", J. Appl. Phys. Lett. 82, 2811-2813, (2003).

Grummon, D.S.; Shaw, J.A.; Gremillet, A. "Low Density Open Cell Foams in the NiTi System", J. Appl. Phys. Lett. 82, 2727, (2003).

Conference Proceedings

Grummon, D.S.; Gotthardt, R.; LaGrange, T. "Planar Extrinsic Biasing of Thin Film Shape-Memory MEMS Actuators for Photolithographic Compatibility", in Surface Engineering 2002-Synthesis, Characterization, and Applications, 599-604, Materials Research Society (2003).

LaGrange, T.B.; Grummon D.S.; Gotthardt, R. "The Influence of Irradiation Parameters on the Behavior of Martensitic titanium nickel thin films", in Defects and Related Phenomena in Intermetallic Alloys, Materials Research Society (USA) 495-500, (2003).

Ni, W.; Cheng, Y-T.; Grummon, D.S. "Characterization of The Shape Memory and Superelastic Effects by Instrumented Indentation Experiments", in Surface Engineering 2002-Synthesis, Characterization, and Applications, 15-20, Materials Research Society (2003).

Ni, W.; Grummon, D.S.; Cheng, Y-T. "Shape Recovery and Stress-Induced Martensite in TiNi Following Indentation and Wear Loading", J. de Phys. IV 112, 1147-1150, (2003).

Grummon, D.S.; laGrange, T. "Composition of Sputtered NiTiX Shape-Memory and Superelastic Thin Films", J. de Physique, IV 112, 853-856 (2003).

LaGrange, T.; Schäublein, R.; Grummon, D.S.; Gotthardt, R. "Nickel Ion Irradiation of Plastically Deformed Martensitic Thin Films", J. de Physique, IV 112, (2003).

Lagrange, T.; Schäublin, R.; Grummon, D.S.; Abromeit, C.; Gotthardt, R. "Irradiation Induced Phase Transformation in NiTi Shape Memory Alloy", Proc. Symp. Microstructural Processes in Irradiated Materials, TMS Annual Meeting, San Diego, CA March 2-6, (2003).

Shaw, J.A.; Gremillet, A.; Grummon, D.S. "The Manufacture of NiTi Foams", Proc. 2002 ASME Int'l Mechanical Engineering Congress and Exposition, IMEC2002/AD-34028, New Orleans, 11/17/02, (2003).

Vestel, M.J.; Grummon, D.S.; Pisano, A.P. "Crystallization of Sputtered NiTi Films", Proc. 2003 ASME International Mechanical Engineering Congress, November 2003, Washington, D.C. USA (IMECE-2003) (2003).

Vestel M.J.; Grummon, D.S. "Precipitates and lamellar microstructures in NiTi films", Proc. ESOMAT-2003: European Symposium On Martensitic Transformations and Shape-Memory, 17-22 August 2003, Royal Agricultural College, Cirencester, UK, (2003).

Ni, W.; Cheng, Y-T.; Grummon, D.S. "Indentation Study of Microscopic Shape Memory and Superelastic Effects in Shape Memory Alloys and Thin Films", Proc. International Conference on Metallurgical Coatings and Thin Films, ICMCTF 2003, April 28 - May 2, 2003, San Diego, CA, (2003).

Ni, W.; Cheng, Y-T.; Grummon, D.S. "Nanoindentaion and Wear Behavior of Nickel Titanium Alloys", Surface Engineering 2001-Fundamentals and Applications, 53-58, Materials Research Society (2002).

Lagrange, T.; Schaublin, R.; Grummon, D.S.; Gotthardt, R. "TEM observations of irradiated titanium-nickel thin films", University of Natal, Proceedings of the 15th International Congress on Electron Microscopy; Volume 1: Physical, Materials and Earth Sciences (South Africa), 963-964, (2002).

Other Works

MSU ID 03-037 "Thin-Film Shape-Memory Actuator Using Polymeric Substrates" provisional patent application submitted by MSU April 2003.

United States Patent Application GP-302875 "Self-Healing Tribological Surfaces", April 8 2003 (application #10/409465) (with General Motors Corp.).

United States Patent Application GP-309219, "Metallic-based Adhesion Materials", march 21, 2003 (application # 10/394,475) (with General Motors Corp.).

Ni, W.; Grummon, D.S.; Cheng, Y-T. "Recovery of microindents in a nickel-titanium alloy: A "self-healing" effect", Bulletin of the American Physical Society 47, 1101, (2002).