无碳化物贝氏体钢 (CFB):第二部分
双辊铸轧镁合金的机械性能
选择性激光烧结 (SLS):第二部分
DataPLUS 模块提供上万种金属材料和非金属材料的腐蚀数据、焊接性能、尺寸与公差信息以及涂层信息。 点击这里了解更多。
Total Materia New Application Launch! 2021年1月14日
Total Materia New Application Launch! 2021年2月10日
Total Materia New Application Launch! 2021年3月10日
在使用Total Materia几个月之后,以及深刻体验过所有潜在功能之后,我非常感谢你们的卓越工作和持续稳定的升级服务。 Total Materia始终是用来达成这一目的唯一工具。
M. Manfredini Bonfiglioli Industrial Gearmotors 博洛尼亚, 意大利
我们的目标很简单,就是让 Total Materia成为全球工程师在材料领域的首选一站式解决方案
Prof. Dr. Viktor Pocajt, CEOKey to Metals AG
This article provides a general overview of cobalt-base alloys as wear-resistant, corrosion-resistant, and/or heat-resistant materials. Particular emphasis is placed on cobalt-base alloys for wear resistance, because this is the single largest application area of cobalt-base alloys.
Cobalt is useful in applications that utilize its magnetic properties, corrosion resistance, wear resistance, and/or its strength at elevated temperatures.
This article provides a general overview of cobalt-base alloys as wear-resistant, corrosion-resistant, and/or heat-resistant materials. Particular emphasis is placed on cobalt-base alloys for wear resistance, because this is the single largest application area of cobalt-base alloys. In heat-resistant applications, cobalt is more widely used as an alloying element in nickel-base alloys with cobalt tonnages in excess of those used in cobalt-base heat-resistant alloys.
The elastic modulus of cobalt is about 210 GPa (30 x 106 psi) in tension and about 183 GPa (26.5 x 106 psi) in compression.
Uses of Cobalt. As well as forming the basis of the cobalt-base alloys discussed in this article, cobalt is also an important ingredient in other materials:
In the nickel-base superalloys, cobalt (which is present typically in the range 10 to 15 wt%) provides solid solution strengthening and decreases the solubility of aluminum and titanium, thereby increasing the volume fraction of gamma prime (?,) precipitate.
The role of cobalt in cemented carbides is to provide a ductile bonding matrix for tungsten-carbide particles. The commercially significant cemented carbides contain cobalt in the range of 3 to 25 wt%. As cutting tool materials, cemented carbides with 3 to 12 wt% Co are commonly used.
Cobalt, which is naturally ferromagnetic, provides resistance to demagnetization in several groups of permanent magnet materials. These include the aluminum-nickel-cobalt alloys (in which cobalt ranges from about 5 to 35 wt%), the iron-cobalt alloys (approximately 5 to 12 wt%). and the cobalt rare-earth intermetallics (which have some of the highest magnetic properties of all known materials).
The artificial isotope cobalt-60 is an important ?-ray source in medical and industrial applications.
As a group, the cobalt-base alloys may be generally described as wear resistant, corrosion resistant, and heat resistant (strong even at high temperatures). Many of the properties of the alloys arise from the crystallographic nature of cobalt (in particular its response to stress), the solid-solution-strengthening effects of chromium, tungsten, and molybdenum, the formation of metal carbides, and the corrosion resistance imparted by chromium. Generally the softer and tougher compositions are used for high-temperature applications such as gas-turbine vanes and buckets. The harder grades are used for resistance to wear.
Historically, many of the commercial cobalt-base alloys are derived from the cobalt-chromium-tungsten and cobalt-chromium-molybdenum ternaries first investigated by Elwood Haynes in the beginning of 20th century. He discovered the high strength and stainless nature of the binary cobalt-chromium alloy, and he later identified tungsten and molybdenum as powerful strengthening agents within the cobalt-chromium system. When he discovered these alloys, Haynes named them the Stellite alloys after the Latin stella (star), because of their star-like luster. Having discovered their high strength at elevated temperatures, Haynes also promoted the use of Stellite alloys as cutting tool materials.
Chemical composition of Stellite alloys is approximately:
Cr ~ 25-30% Mo = 1% max W = 2-15% C ~ 0.25-3.3% Fe = 3% max Ni = 3% max Si = 2% max Mn = 1% max. Co = rest of balance
Types of wear. There are several distinct types of wear which generally fall into three main categories:
Abrasive wear is encountered when hard particles, or hard projections (on a counter-face) are forced against, and moved relative to a surface. The terms high and low stress abrasion relate to the condition of the abrasive medium (be it hard particles or projections) after interaction with the surface. If the abrasive medium is crushed, then the high stress condition is said to prevail. If the abrasive medium remains intact, the process is described as low stress abrasion. Typically, high stress abrasion results from the entrapment of hard particles between metallic surfaces (in relative motion), while low stress abrasion is encountered when moving surfaces come into contact with packed abrasives, such as soil and sand.
In alloys such as the cobalt-base wear alloys, which contain a hard phase, the abrasion resistance generally increases as the volume fraction of the hard phase increases. Abrasion resistance is, however, strongly influenced by the size and shape of the hard phase precipitates within the microstructure and the size and shape of the abrading species.
Sliding Wear. Of the three major types of wear, sliding is perhaps the most complex, not in concept, but in the way different materials respond to sliding conditions. Sliding wear is a possibility whenever two surfaces are forced together and moved relative to one another. The chances of damage are increased markedly if the two surfaces are metallic in nature, and if there is little or no lubrication present.
Today, the use of high-temperature alloys is more diversified, as more efficiency is sought from the burning of fossil fuels and waste, and as new chemical processing techniques are developed.
In general, cobalt-base high-temperature alloys have the following chemical composition:
Cr = 20-23% W = 7-15% Ni = 10-22% Fe = 3% max C = 0.1-0.6% Co = rest of balance.
Although cobalt-base alloys are not as widely used as nickel and nickel-iron alloys in high-temperature applications, cobalt-base high-temperature alloys nevertheless play an important role, by virtue of their excellent resistance to sulfidation and their strength at temperatures exceeding those at which the gamma-prime- and gamma-double-prime-precipitates in the nickel and nickel-iron alloys dissolve. Cobalt is also used as an alloying element in many nickel-base high-temperature alloys.
By virtue of their homogeneous microstructures and lower carbon contents, the wrought cobalt-base high-temperature alloys (which typically contain tungsten rather than molybdenum) are even more resistant to aqueous corrosion, but still fall well short of the nickel-chromium-molybdenum alloys in corrosion performance.
To satisfy the industrial need for alloys which exhibit outstanding resistance to aqueous corrosion, yet share the attributes of cobalt as an alloy base (resistance to various forms of wear, and high strength over a wide range of temperatures), several low-carbon, wrought cobalt-nickel-chromium-molybdenum alloys are produced.
Chemical composition of these alloys is:
Cr = 20-25% W = 2% Mo = 5-10% Ni = 9-35% Fe = 3% max C = 0.8% max N = 0.1% max Co = rest of balance.
Date Published: Sep-2002
输入搜索词:
搜索项
全文 关键字
标题 摘要
Physical properties are available for a huge number of materials in the Total Materia database.
Data is available through official information from standards and also through Total Materia unique similar materials cross referencing functionality, adding another dimension to your search for physical properties data!
Enter the material of interest into the quick search field. You can optionally narrow your search by specifying the country/standard of choice in the designated field and then clicking "Search".
After selecting the material of interest to you, click on the Physical Properties link to view data for the selected material. The number of physical property data records is displayed in brackets next to the link.
Physical properties are displayed according to the origin of the data set. Official data from standards can be found under the official tab, data deriving from other sources for the material will also be displayed under its own tab.
The similar materials tab displays all materials that are similar to the original material and have physical properties inserted. This can be very handy when looking for equivalent materials!
The typical tab gives a generic overview of property data for the material for you to use as a useful starting point for further investigation.
For you’re a chance to take a test drive of the Total Materia database, we invite you to join a community of over 150,000 registered users through the Total Materia Free Demo.