Research on the Material Differences of 7050-T7451 Aluminum Alloy

Microstructure analysis and tensile fracture analysis were conducted on the domestic and imported 7050-T7451 aluminum alloy to investigate the material differences between them. Tensile test shows that the yield strength and tensile strength of domestic 7050-T7451 aluminum alloy are both higher than imported 7050-T7451 aluminum alloy, however, the material elongation and the reduction of area are both lower than imported material. Microstructure analysis shows that compared with domestic 7050-T7451 aluminum alloy, in the imported 7050-T7451 aluminum alloy, the degree of recrystallization and anisotropy is less, and the grain size is smaller. In addition, the transition from material surface to center organization of imported 7050-T7451 aluminum alloy is more smooth and uniform than domestic material. From tensile fracture analysis, it concluded that the domestic 7050-T7451 aluminum alloy has large grain size, low structural homogeneity, and little toughness characteristic of fracture, and those characteristics cause low elongation and low reduction of area of domestic 7050-T7451 aluminum alloy.

Research on the Mechanical Behavior of High Strength Concrete

Bases on experimental investigations of HSC and NSC, HSC’s mechanical behavior, failure mechanism, fracture toughness, characteristic length and damage feature are discussed in the paper, and the formula for flexural strength and comparative toughness is given. The results show that the HSC has a good uniformity of structural entity and large cracking resistance. In addition, HSC is more brittle and more vulnerable to damage than NSC.

Evaluation of Fracture Toughness Characteristic for Nuclear Piping Using Various Types of Specimens

The leak-before-break (LBB) concept is based on the fracture resistance curve obtained by J-R tests on various types of specimens. But it has been also known that the fracture toughness data by various types of specimens are different each other. For example, the estimates for fracture toughness of standard specimens are conservative when compared to the fracture toughness of real pipes owing to the difference of the constraint effect between real pipes and standard specimens. Therefore for estimating the integrity of real pipes on the basis of elastic-plastic fracture mechanics, we have to first establish the relations among real pipes, standard CT specimens and curved CT specimens. In this study, we performed the fracture toughness tests for nuclear piping material by various types of specimen. And each J-R curve considered in the constraint effect was compared.

AISI TYPE M7

AISI Type M7 is a molybdenum type of high-speed steel having improved cutting efficiency over AISI Type M1 high-speed steel. Type M7 was designed to offer increased wear resistance while retaining the toughness characteristic of molybdenum-type high-speed steels. It is suitable for a wide variety of cutting-tool applications where improved resistance to abrasion is desired. Typical applications include twist drills, end mills, form tools, reamers and milling cutters. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, and surface treatment. Filing Code: TS-468. Producer or source: Tool steel mills. See also Alloy Digest TS-483, October 1987.

AL TECH LMW-V

AL Tech LMW-V is a molybdenum-type high-speed steel used extensively by domestic cutting-tool makers. It was designed to offer increased wear resistance while retaining the toughness characteristic of molybdenum-type high-speed steels. It is suitable for a wide variety of cutting-tool applications where improved resistance to abrasion is desired. Typical applications include twist dri milling cutters. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, and machining. Filing Code: TS-353. Producer or source: AL Tech Specialty Steel Corporation.