Titanium is an important structural metal that was developed in the 1950s; titanium alloys are characterized by high strength, excellent corrosion resistance, and high heat resistance.
By the mid-1960s, titanium and its alloys were already being used in general industry for applications such as electrodes in the electrolysis industry, condensers in power plants, heaters in oil refining and desalination, and environmental pollution control equipment. Titanium and its alloys have become a corrosion-resistant structural material. Today, we will explore the significance of the mechanical properties of titanium alloys.
1. Tensile Strength
Tensile strength is the critical value at which a metal transitions from uniform plastic deformation to localized plastic deformation; it also represents the maximum load-bearing capacity of a metal under static tensile conditions. For ductile materials, it characterizes the material's resistance to maximum uniform plastic deformation. Before a tensile specimen reaches its maximum tensile stress, deformation is uniform and consistent; however, once this stress is exceeded, the metal begins to exhibit necking, i.e., localized deformation. For brittle materials with no (or very little) uniform plastic deformation, it reflects the material's fracture resistance. The symbol is RM, and the unit is MPa.
Tensile strength (Rm) refers to the maximum stress a material can withstand before breaking. Currently, the most common method for measuring tensile strength in China involves using universal testing machines to determine a material's tensile and compressive strengths!
2. Yield strength
This refers to the yield point at which a metallic material begins to yield, or the stress required to cause a small amount of plastic deformation. For metallic materials that do not exhibit a distinct yield point, the stress value required to produce 0.2% residual deformation is defined as the yield point, also known as the conditional yield point or yield strength. An external force exceeding this limit will cause permanent failure of the component, from which it cannot recover. For example, the yield limit of low-carbon steel is 207 MPa; when subjected to an external force greater than this limit, the component will undergo permanent deformation, whereas forces below this limit will allow the component to return to its original shape.
Yield strength, also known as the yield limit and commonly denoted by the symbol δs, is the critical stress value at which a material yields.
3. Hardness
(1) Rockwell Hardness
This method determines hardness values based on the depth of plastic deformation in the indentation. One unit of hardness is defined as 0.002 millimeters. When HB > 450 or the specimen is too small, the Brinell hardness test cannot be used, and Rockwell hardness measurement must be employed instead. This method involves pressing a diamond cone with a 120° apex angle or a steel ball with a diameter of 1.59 or 3.18 mm into the surface of the material under a specific load, and determining the material's hardness based on the depth of the indentation.
2) Brinell Hardness
Brinell hardness (HB) is generally used for softer materials, such as non-ferrous metals and steel before heat treatment or after annealing. Rockwell hardness (HRC) is generally used for harder materials, such as those that have undergone heat treatment.
(3) Vickers Hardness
The principle behind the measurement of Vickers hardness is essentially the same as that of Brinell hardness; it also calculates the hardness value based on the load per unit area of the indentation. The difference lies in the indenter used in the Vickers hardness test, which is a diamond tetrahedral pyramid.
E-mail: garychen3215@hotmail.com
Address: No.35, Baoti Rd, Baoji city, Shaanxi Province, China
Contact: Mr. Gary Chen
Phone: +86-917-8883215
Mobile/WhatsApp: +86 13092900605
