Polymer materials are key building blocks of the modern world, commonly used in packaging, automobiles, building materials, electronics, telecommunications, and many other industries. These commercial applications of polymeric materials would not be possible without the use of additives. This article is divided into five sections: mechanical property modifiers, physical property modifiers, biological function modifiers, processing aids, and colorants. It describes three classes of additives that are used to inhibit biological activity, six classes of mechanical property modifiers, three classes of physical property modifiers, and two classes of both colorants and processing aids.

This article reviews the impact response of plastic components and the various methods used to evaluate it.. It describes the effects of loading rate on polymer deformation and the influence of temperature and strain rate on failure mode. It discusses the advantages and limitations of standard impact tests, the use of puncture tests for assessing material behavior under extreme strain, and the application of fracture mechanics for analyzing impact failures. It also develops and demonstrates the theory involved in the design and analysis of thin-walled, injection-molded plastic components.

This datasheet provides information on composition limits, fabrication characteristics, processing effects on physical and mechanical properties, and applications of aluminum alloy 7039.

From the point of view of economics and ecology, thin-wall ductile iron (TWDI) castings can compete in terms of mechanical properties with the light castings made of aluminum alloys. This article discusses the effect of technological factors on the cooling rate and physicochemical state of the liquid metal for preparing thin-wall castings with good mechanical properties and performance while avoiding casting defects. It describes a variety of defects that may appear during the production of TWDI castings, such as casting skin anomalies (e.g., flake graphite, graphite segregation), graphite clusters, exploded graphite, slag inclusions, shrinkage porosity, eutectic chill and secondary carbides, and cold shuts. The article reviews the tensile, fatigue, impact, and wear properties of TWDI castings. It provides information on the production and applications of TWDI castings.

According to the ISO 16112 standard for compacted graphite cast irons (CGIs), the graphite particles in CGIs shall be predominantly in the vermicular form when viewed on a two dimensional plane of polish. This article begins with a schematic illustration of compacted graphite microstructures with nodularity. It describes the tensile properties, hardness and compressive properties, and impact properties of CGI. The article concludes with a discussion on the fatigue strength and thermal conductivity of CGI.

The main factors affecting the mechanical properties of compacted graphite irons both at room temperatures and at elevated temperatures are composition, structure (nodularity and matrix), and section size. This article presents a comparison between some properties of flake graphite (FG), compacted graphite (CG), and spheroidal graphite (SG) irons in a table. It discusses the effects of composition, structure, and section size on the mechanical properties of compacted graphite irons. The compressive and shear properties, modulus of elasticity, impact properties, fatigue strength, and elevated-temperature properties of compacted graphite irons are also reviewed.

This article focuses on heat treating of the most important H-series and low-alloy hot-work tool steels, namely, normalizing, annealing, stress relieving, preheating, austenitizing, quenching, tempering, and surface hardening. It describes the heat-treating procedure for hot-work tools using examples. The article provides information on the North American Die-Casting Association's requirements for steel grades and heat treatment of dies made of hot-work tool steels. It also describes the chemical compositions and mechanical and metallurgical properties of hot-work tool steels.

This article begins with an overview of classes and applications of gray iron. It discusses the castability of gray iron in terms of section sensitivity and fluidity. The article provides information on the dimensions of prevailing sections recommended for gray irons and reviews the properties and specifications of test bar. Properties of gray iron, such as fatigue limit, pressure tightness, impact resistance, machinability, and dimensional stability, at both room and elevated temperature, are reviewed. Wear behavior of gray iron castings during sliding contact under conditions of normal lubrication is also discussed. The article evaluates the use of alloys and heat treatment to modify as-cast properties. It concludes with information on the physical properties of gray iron castings.

This article reviews the graphite morphology, chemical composition requirements, castability, mechanical properties, and corrosion resistance of compacted graphite (CG) irons. It describes the factors affecting the mechanical properties of CG irons. The article also presents the advantages of CG irons.

This article describes methods for analyzing impact-damaged composites in the aircraft industry. These include C-scan and x-radiography methods and optical microscopy. The article reviews brittle-matrix composite and tough-matrix composite failures. It explains the different types of composite failure mechanisms such as thermoplastic-matrix composite failure mechanisms, untoughened thermoset-matrix composite failure mechanisms, toughened thermoset-matrix composite failure mechanisms, dispersed-phase and rubber-toughened thermoset-matrix composite failure mechanisms, and particle interlayer-toughened composite failure mechanisms.

This article describes the synthesis, manufacturing, and properties of both the neat soy-based resins and the glass, flax, and hemp composites. A tabulation of the fatty-acid distribution in various plant oils is provided. The article discusses synthetic pathways for triglyceride-based monomers and provides a discussion on acrylated epoxidized soybean oils (AESO), maleinized soyoil monoglyceride (SOMG/MA), and maleinized hydroxylated oil (HO/MA). The polymer properties of the AESO, SOMG/MA, and HO/MA are also discussed. The article explains the ballistic impact resistance of soy resin composites and concludes with a discussion on biodegradable composites.

Advanced thermoplastic composites possess impact resistance, fracture toughness, and elevated temperature endurance properties due to their melt-fusible nature. This article presents the material options available for thermoplastic composites such as pseudothermoplastics, post-impregnated thermoplastics, and true thermoplastics. It describes the processing methods of thermoplastic composites, including weaving, seaming, autoclaving, preconsolidation, roll consolidation, roll forming/pultruding, thermoforming, press forming, hydroforming, and diaphragm forming. The article provides information on different types of joints, namely, fastened, adhesive bonded, dual polymer bonded, co-consolidated, and welded joints. It explains the joining methods of thermoplastic composites, such as press forming, diaphragm forming, autoclaving, ultrasonic welding, resistance welding, and induction welding.

This article discusses the standard test methods that can be applied to many types of welds: tension, bending, impact, and toughness testing. It provides information on four qualification stages, namely, the weld material qualification, base material qualification, the weld procedure qualification, and the weld service assessment. The article describes two general types of measurements for residual stress in welds: locally destructive techniques and nondestructive techniques. Locally destructive techniques include hole drilling, chip machining, and block sectioning. Nondestructive techniques include X-ray diffraction, neutron diffraction, Barkhausen noise analysis, and ultrasonic propagation analysis. The article concludes with an overview of weldability testing.

The key to any successful part development is the proper choice of material, process, and design matched to the part performance requirements. Understanding the true effects of time, temperature, and rate of loading on material performance can make the difference between a successful application and catastrophic failure. This article provides examples of reliable material performance indicators and common practices to avoid failure. Simple tools and techniques for predicting part mechanical performance integrated with manufacturing concerns, such as flow length and cycle time, are demonstrated. The article describes the prediction of mechanical part performance for stiffness, strength/impact, creep/stress relaxation, and fatigue.

This article reviews the tensile properties and toughness characteristics of discontinuously reinforced aluminum (DRA) composites in terms of particle spacing, particle size, volume fraction, matrix alloy, and matrix microstructure. Both fracture toughness data and impact toughness data of the DRA composites are summarized. The article discusses the effects of confining pressure on the ductility of the DRA materials. It describes the fatigue behavior, such as stress-life behavior, strain-life behavior, and fatigue crack propagation, of the DRA.

Explosion welding (EXW), also known as explosive bonding, is accomplished by a high-velocity oblique impact between two metals. This article describes the practice of producing an explosive bond/weld and draws on many previous research results in order to explain the mechanisms involved. It provides a schematic illustration of the arrangement used in the parallel gap explosive bonding process. The article discusses several important concepts pertaining to explosive parameters, hydrodynamic flow, jetting, and metal properties. It summarizes the criteria used to model the explosive bonding process. The article describes bond morphology in terms of wave formation, bond microstructure, and bond strength determination.

ASTM specification A 48 classifies gray irons in terms of tensile strength. The usual microstructure of gray iron is a matrix of pearlite with graphite flakes dispersed throughout. Section sensitivity effects are used in the form of a wedge test in production control to judge the suitability of an iron for pouring a particular casting. Mechanical property values obtained from test bars are sometimes the only available guides to the mechanical properties of the metal in production castings. Gray iron castings are used widely in pressure applications such as cylinder blocks, manifolds, pipe and pipe fittings, compressors, and pumps. Where high impact resistance is needed, gray iron is not recommended. The machinability of most gray cast iron is superior to that of most other cast irons of equivalent hardness, as well as to that of virtually all steel. Gray iron is used widely for machine components that must resist wear.