Resonant ultrasound spectroscopy (RUS) is an emerging ultrasonic measurement technique. By measuring the natural vibrational frequencies of test samples, RUS can determine Young's modulus, shear modulus, and Poisson's ratio for isotropic materials. By comparing the vibrational spectra of a test sample to those obtained from a standard, it is possible to infer the causes of the differences (if any) and detect various part defects, such as size variations, cracks, and pores. Thanks to advances in computer technology, codes and software are now available for data reduction, analysis, and interpretation. This article addresses fundamentals of the technology and applications in research and industry.

This article describes new software that helps predict properties of high-entropy alloy compositions under high-temperature conditions. The tool was developed by extensive testing on the quinary Al-Co-Cr-Fe-Ni alloy system with both first-principles density functional theory calculations and machine learning to establish a substantial database for modeling.

Novel bcc CoCr-base alloys exhibit a Young’s modulus similar to human bone combined with superelastic strain twice that of NiTi alloys.

As scientists and engineers continue to develop and investigate replacement tissues for patient disease, injury, and aging, proper mechanical characterization of biological materials is critical. This article provides an overview of some static mechanical testing, creep testing, stress-relaxation testing, and fatigue testing methods for biomaterials applications.

Ductile fracture toughness testing is useful for evaluating a material’s structural integrity. This article briefly reviews three widely used J-integral vs. crack growth resistance (J-R) curve test methods for metals: elastic unloading compliance, normalization, and direct current potential drop. The J-Integral calculation is the same in all three methods, with differences primarily involving crack size measurements.

Atomic force microscopy studies show that sharp yield points in steels are explained by the existence of hard grain boundary walls, contrary to current accepted theories.

Recently developed open-source software based on standard test and normalization methods simplifies the process of generating J-integral versus crack-growth resistance (J-R) curves to evaluate fracture toughness in the ductile region.

Materials testing systems must be robust and flexible, capable of determining the mechanical properties of a broad range of materials and components ranging from metals to composites and from plastics to natural, bio-based materials. This article provides an overview of electromechanical testing systems, servohydraulic systems, and vibrophores for high cycle fatigue testing.

Dissimilar metals, each with their own special properties, can be integrated into a single composite wire to achieve a functionally driven design. Simultaneously strong, stiff, and superelastic guidewires that provide proximal stiffness and distal flexibility for medical applications are discussed in this article.

In this brief case study, finite element analysis and linear elastic fracture mechanics are used to evaluate new weld designs for large marine engines.

A recent metallographic and historical analysis of two parts from the Buenos Aires to Pacific Railroad railway looked at possible manufacturing techniques of the parts in question. The information collected is useful for comparison with techniques and materials used at that time as well as with current techniques. The analysis questioned whether the material itself has varied or evolved from the metallurgical point of view, and confirmed the quality of raw material used to construct the historic railway line.

Steel rebar is commonly used around the world to reinforce concrete. Understanding the basics of rebar tensile testing is critical to ensuring product quality. This article addresses issues in rebar tensile testing that are commonly misinterpreted or misunderstood by users.

Researchers at the University of Michigan are investigating the complex heterogeneous phase transformations associated with deformation in shape memory alloys by means of in-situ tensile loading in combination with SEM, EBSD, and digital image correlation. This article describes the general approach and presents and interprets test results.

This article describes research aimed at developing cast aluminum alloys with the necessary high-temperature tensile and fatigue strengths to withstand the modern automotive engine environment. Micro-additions of Ti, V, and Zr were added to an Al-7Si-1Cu-0.5Mg cast alloy, leading to the formation of phases that increase stability at high temperatures, positively affecting alloy strength.

Pure screw dislocations can become helical by absorbing defects such as vacancies and develop attractive interaction with another helical dislocation to form a double helix structure.

Modeling shows that achieving required gear performance in a reduced gear size is possible by changing the steel grade and heat treatment parameters during the design stage. This article describes work in which virtual computer models using DANTE software are applied to help achieve gear size reduction by including steel grade hardenability and heat treatment parameters in the design process.

Selective-melt sintering is faster and more efficient than the methods currently used to make high-density ceramics. This article explains how applied electric fields contribute to the formation of metallic precipitates at grain boundaries and how defect segregation and field-assisted migration generate heat near dislocations and in grain boundaries, reducing flow stress and retarding grain growth in the solid state.

Techniques for the 3D printing of ceramics are evolving beyond product development and prototypes to enable full production-scale operations. This article gives examples of available methods and tradeoffs that must be addressed in developing 3D printing systems for ceramics.

New research explores a zirconia-based shape memory ceramic that exhibits a unique type of electrically triggered martensitic transformation.

Cross-linked low density polyethylene (LDPE) foams are used for applications such as packaging and thermal insulation. Relating composition, process, and dimensional variables with materials properties using nonlinear modeling provides a valuable tool for efficient LDPE materials and product development.