Mechanical Properties of Materials MMM 220 Test Methods Updated: Oct. 28, 2009 Ali Osman Kurt (M.Sc. and Ph.D. in Materials Science) www.aokurt.sakarya.edu.tr

Introduction Relationships in Materials Science Structure Properties Processing

Properties Properties are evaluate by TESTING named as tension, compression, hardness, bending, torsion, high strain rate, creep, fatigues, fracture, corrosion, formability, wear, and some others.

Testing Each test should / may be carried out according to a standard, i.e. a set of instruction to follow in order to obtain data useful to drive the materials properties. Some examples for such standards are as follows; «Standard Test Methods and Definitions for Mechanical Testing of Steel Products» ASTM A370-15 «Standard Test Method for Brinell Hardness of Metallic Materials» ASTM E10 – 12 «Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics» ASTM C1327-15

Sample: Tension Testing “Tension Testing consists of subjecting a prepared specimen of special size and shape, or a full-size specimen, to a gradually increasing uniaxial load (stress) until failure occurs.”1 The example for such test standard is ASTM D638 «Standard Test Method for Tensile Properties of Plastics». 1: C.S. Barrett, Crystal Structure of Metals, ASM Handbook, Volume 8, Metallography and Microstructures, ASM International, 1990, in ASM Handbook on DVD, ASM International and The Dialog Corporation, 1999.

Tension Testing and Results Uniform strain before necking begines. Fracture stress. Strain to fracture is given as Λl. The tensile strength, yield strength, yield point, percent elongation, reduction in area. TENSION TESTING consists of subjecting a prepared specimen of special size and shape, or a full-size specimen, to a gradually increasing (static) uniaxial load (stress) until failure occurs. The operation is accomplished by gripping opposite ends of the workpiece and pulling it, which results in elongation of the test specimen in a direction parallel to the applied load.

Sample: Hardness Testing “Hardness test is the measures of the material to penetration by a sharp object”1” Common hardness tests are Brinell, Rockwell and Vickers. 1: Donald R. ASKELAND, "The science and engineering of materials“, 3rd Edi., p147, 2003.

Hardness Testing - Brinell Brinell hardness test: A hard steel ball (usually 10 mm in diameter) is used. 3000 kg – Cast iron and steel 500 kg – Nonferrous alloys

Hardness Testing - Rockwell Rockwell hardness test: A diamond cone (120o) and hard carbide (or steel balls) usually 1/16 in. (1.5875mm) or 1/8 in. (3.175mm) in diameter are used. RA – 60 kg – Very hard materials RB – 100 kg – Brass, low strength steels RC – 150 kg – High-strength steels RD – 100 kg – High-strength steels RE – 100 kg – Very soft materials RF – 60 kg – Al, soft materials

Hardness Testing - Vickers Vickers hardness test is a microhardness test. A diamond pyramid (136o) is used for indentation. 10 kg – Hard materials (such as ceramics)

Conclusions Materials properties are effected by its structure and processing method(s). Required properties are checked by a set of pre-determined instructions, which are formally named standard for testing.

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