Fabrication, modeling, and characterization of porous shape memory alloys

This paper will present powder metallurgical methods for producing porous NiTi from elemental powders of 50at% Ni and 50at% Ti using a sintering approach in a high pressure environment. Different pore sizes and volume fractions of NiTi SMAs are fabricated and characterized in terms of composition and phase transformation characteristics using calorimetric measurements. Quasi-static and dynamic loading experiments are conducted on samples produced with the presented methodology and their shape recovery and energy absorption characteristics are measured during the forward and reverse phase transformation and detwinning. A micromechanical averaging method for modeling the behavior of porous SMAs is presented. Correlation of experimental results with theoretical predictions of the micromechanical method for the case of quasi-static loading is discussed.

[1]  P. A. Blenkinsop,et al.  Manufacture of a novel porous metal , 1987 .

[2]  D. Lagoudas,et al.  Numerical implementation of a shape memory alloy thermomechanical constitutive model using return mapping algorithms , 2000 .

[3]  D. Lagoudas,et al.  Modeling of the thermomechanical behavior of porous shape memory alloys , 2001 .

[4]  D. Lagoudas,et al.  A UNIFIED THERMODYNAMIC CONSTITUTIVE MODEL FOR SMA AND FINITE ELEMENT ANALYSIS OF ACTIVE METAL MATRIX COMPOSITES , 1996 .

[5]  T. Bateman,et al.  Effect of nitinol implant porosity on cranial bone ingrowth and apposition after 6 weeks. , 1999, Journal of biomedical materials research.

[6]  V Brailovski,et al.  Review of shape memory alloys medical applications in Russia. , 1996, Bio-medical materials and engineering.

[7]  D. Schwartz,et al.  Development and Scale-up of the Low Density Core Process for Ti-64 , 1998 .

[8]  Friedrich K. Straub,et al.  Applications of torsional shape memory alloy actuators for active rotor blade control: opportunities and limitations , 1996, Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[9]  Eric L. Vandygriff,et al.  Modeling of thermomechanical response of porous shape memory alloys , 2000, Smart Structures.

[10]  Dimitris C. Lagoudas,et al.  Development of a shape memory alloy actuated biomimetic vehicle , 2000 .

[11]  Christopher A. Martin,et al.  Shape memory alloy TiNi actuators for twist control of smart wing designs , 1996, Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[12]  Hu Chun Yi,et al.  The combustion synthesis of Ni-Ti shape memory alloys , 1990 .

[13]  R. Hill.  A self-consistent mechanics of composite materials , 1965 .

[14]  Ted A. Bateman,et al.  Porous Materials for Bone Engineering , 1997 .