The Fourth International Cryogenic Materials Conference (ICMC) was held in San Diego, California in conjunction with the Cryogenic Engineer ing Conference (CEC) on August 10-l4, 1981. The synergism produced by conducting the two conferences together remains very strong. In the ap pl1cation of cryogenic technology, materials continue to be a demanding challenge, and sometimes, an obstacle. The association of materials and cryogenic engineers increases their awareness of recent research in each other's fields and influences the course of future research. Many contributed to the success of the 1981 conference. J. W. Morris of the University of California--Berkeley was ICMC Conference Chairman. E. N. C. Dalder of Lawrence Livermore Laboratories was ICMC Structural Program Chairman; D. C. Larbalestier of the University of Wisconsin- Madison, and D. K. Finnemore of Iowa State University were Superconducting Materials Program Chairmen. Local arrangments were expertly coordinated by R. E. Tatro of General Dynamics--San Diego. The CEC Board, especia11y their conference chairman, T. M. Flynn, of the National Bureau of Stan dards, Boulder, contributed very substantia1ly to conference planning and implementation. All of their efforts provided the foundation of the largest CEC/ICMC ever. We thank the Office of Naval Research and the Office of Fusion Energy and Basic Energy Sciences of the Department of Energy for providing needed financial support for the conference. Fina11y, we especially thank M. Stieg, who prepared the papers for the new procedures and format used in this volume.

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General Reviews.- Low-Temperature Materials Research: A Historical Perspective (Invited).- Mechanical Property Measurements at Low Temperatures (Invited).- Recent Developments in Filamentary Compound Superconductors (Invited).- Powder Metallurgy Processes A Review Of The Status And Promise (Invited).- Structural Alloys.- Deformation of Metastable Austenitic Steels at Low Temperatures.- Discontinuous Deformation Modes of a Nitrogen-Stabilized Austenitic Steel.- The Influence of Magnetic Structure on Temperature Dependence of the Yield Strength of 20cr-16ni-6mn Steel at Very Low Temperatures.- Mechanical Evaluation of Nitrogen-Strengthened Stainless Steels at 4 K.- Tensile and Fracture Properties of Manganese-Modified AISI 304 Type Stainless Steel.- Mechanical Properties of High Manganese Steels at Cryogenic Temperatures.- High-Alloy Manganese-Aluminum Steels for Cryogenic Applications.- Properties of Low-Carbon 25Mn-5Cr-1Ni Austenitic Steel for Cryogenic Use.- Crack Initiation and Arrest Characteristics of 9%Ni Steels with Various Charpy V-Notch Energy Values.- The Use of Low-Temperature Strengthening of Steels in Welded Cryogenic Structural Codes.- Nonmetallics and Composites.- A Review of the Effects of Ionising Radiation on Plastic Materials at Low Temperatures (Invited).- Mechanical Performance of Graphite- and Aramid-Reinforced Composites at Cryogenic Temperatures.- Reinforced Polymers at Low Temperatures (Invited).- Degradation of Fiber-Reinforced Composite Materials at Cryogenic Temperatures, Part I Uniaxial Tensile and Pure Torsional Fatigue.- Degradation of Fiber-Reinforced Composite Materials at Cryogenic Temperatures, Part II Multiaxial Fatigue.- Characterization of Glass-Reinforced Composites for Cryogenic Applications (Invited).- Mechanical Properties of an Insulator for the Japanese LCT Coil.- The Manufacture and Properties of Radiation Resistant Laminates (Invited).- Mechanical and Thermal Properties of Glass-Fiber-Reinforced Composites at Cryogenic Temperatures.- Compressive Tests of Composite Tubes at 300 K and 77 K.- Impact Tests of Reinforced Plastics at Low Temperatures.- Current Status of Standardized Nonmetallic Cryogenic Laminates.- Concrete: Compressive Properties, Flexural and Splitting Strengths, and KIc at Low Temperatures.- Tensile, Compressive, and Shear Properties of Polyurethane Foam at Low Temperatures.- Cryogenic Tests of Glass-Epoxy-Based Electrical Insulation.- Flux Pinning in Superconductors.- Flux Pinning in High-Current-Carrying Superconductors (Invited).- Flux Pinning for In Situ Prepared Superconducting Composites.- Neutron Irradiation of NbTi with Different Flux Pinning Structures.- Alpha-Titanium Precipitation in Niobium-Titanium Alloys.- High-Field Superconductors.- New Perspectives on the Physics of High-Field Superconductors (Invited).- The Phase Relationships in Nb3Sn Wires at Low Temperatures as Detected by Crystallographical (Neutron and X-Ray Diffraction) and by Physical [BC2(T), Jc vs. ?] Measurements.- Low Temperature Structural Transformations in Powdered Samples of Nb3Sn.- Superconducting Properties of (Nb,Ti)3Sn Wires Fabricated by the Bronze Process.- Effects of the IVa Element Additions on Composite-Processed Nb3Sn.- A15 Superconductors.- Phase Relationships, Basic Metallurgy, and Superconducting Properties of Nb3Sn and Related Compounds (Invited).- The Layer Thickness Dependence of the Transition Temperature in Niobium-TIN.- Superconducting Current Densities in Bronze-Processed Nb3Sn Multifilamentary Wires.- An Investigation of the Enhancement of the Critical Current Densities in Bronze-Processed Nb3Sn.- The Properties of Multifilamentary Wires on Nb3Sn Base Prepared by the Hydroextrusion Method.- Effects of Ternary Additions on Young's Modulus and the Martensitic Transformation of Nb3Sn.- Multifilamentary Nb-Hf/Cu-Sn-Ga Composite Wires.- Formation of Multifilamentary V3Ga with V-5 to -7 Atomic Percent Ga Alloys.- Developmental Studies on Powder-Processed Nb3Al Superconducting Wire.- Multiply-Connected Superconductors.- Optimization of Critical Currents in Cu-Nb3Sn Microcomposites.- On the Optimization of InSitu Nb3Sn Wire.- Temperature Dependence of Jc for InSitu Superconductors.- High-Field Critical Current and Mechanical Properties of InSitu Processed V3Ga Superconductors.- Development of Cryostabilized Nb3Sn-Cu Superconducting Wire Using the InSitu Process.- Testing Results of Multifilamentary Nb3Sn Composites Made by a Modified Jellyroll Method.- Hydrostatic Extrusion of InSitu Process Superconductive Wire for Use in NMR Magnets.- Fabrication of Stabilized InSitu Nb3Sn Wire by Consumable Arc Melting and its Magnetic Behavior.- Continuous High Temperature Gradient Solidification of InSitu Cu-Nb Alloys for Large-Scale Development.- Superconductor Properties and Measurements.- Effect of Twist Pitch on Short-Sample V-I Characteristics of Multifilamentary Superconductors.- End Effects on the Loss for Short Superconductors.- Two-Dimensional Analysis of AC Loss in Superconductors Carrying Transport Current.- The Specific Heat of NbTi from 0 to 7 T Between 4.2 and 20 K.- Field Emission and Secondary Electron Emission from Nb3Sn Surfaces.- Investigation on the Physical Mechanism Underlying the Function of a Fast Gold-Tin Metal Film Second-Sound Detector.- Effect of the Diffusion Barrier on the Magnetic Properties of Practical Nb3Sn Composites.- Strain Effects in Superconductors.- Strain Tolerances in Nb3Sn Conductors.- On the Interaction of Stress with the Martensitic Phase Transition in A15 Compounds.- The Effect of High Compressive Stress on the Critical Current in Multistrand Nb3Sn Conductors.- Experimental Test of Stress Scaling Law in Superconducting V and Nb.- Superconducting and Mechanical Properties of Cold Hydrostatically Extruded Monofilamentary Nb3Sn Wires.- Superconductor Performance.- Recent Developments on Methods for Superconductor Joining.- Electrical Boundary Resistance in an Aluminum-Stabilized Superconductor.- Structural Aspects of Cable Conductors in High-Field- Strength, High-Current-Density Superconducting Dipoles.- Training Studies of Epoxy-Impregnated Superconductor Windings.- Stability Measurements of Aluminum-Stabilized Nb-Ti Bronze Matrix Nb3Sn Potted Superconducting Magnets.- Transient Performance of a Prereacted, Fully Impregnated Multifilamentary Nb3Sn Coil.- Fabrication - Superconduc…