What is the relationship between the properties and composition of alloys?

will change the properties and composition of the alloy.

A substance with metallic properties formed by fusing two or more metals (or metals and non-metals) is called an alloy. The alloy has many superior physical, chemical or mechanical properties than its constituent metals. For example, duralumin (containing a small amount of silicon, the rest is aluminum), has good mechanical properties, high strength and easy processing, and low density, can be used as a lightweight structural material.

At present, more than 60% of the aluminium produced in countries around the world is used to make alloys. The alloy of aluminum is mainly to add copper, magnesium, zinc, manganese, silicon and other elements to aluminum, and sometimes chromium, titanium, beryllium and other elements. Many alloys have a lower melting point than the melting point of their constituent metals.

For example, the melting point of aluminum-silicon alloy (silicon, magnesium, copper, and manganese contained in addition to aluminum) is lower than that of each component metal. For example, the melting point of tin is, the melting point of lead is, and the melting point of the alloy composed of tin and lead according to 2 1 is 180, which is lower than the melting point of tin or lead, and this alloy is commonly used solder. Another example is the "Wood alloy" used as a fuse material, which is an alloy composed of tin, bismuth, cadmium and lead according to the mass ratio of 1 4 1 2, with a melting point of only 67, which is lower than the boiling point of water.

Therefore, when the current on the circuit is too large and the wire heats up to about 70, the fuse can be melted and the circuit will be automatically cut off to ensure the safety of electricity. Pressure cooker fusible sheet, which is now quite widely used, is also a low melting point alloy. When the pressure valve passage of the pressure cooker is blocked, the pressure in the pot increases, and the temperature rises to the melting point of the molten sheet, the melting path of the fusible disc is opened, so that the pressure in the boiler is reduced and the temperature is cooled, so as to ensure the safety of use.

However, the melting points of the constituent metals that make up the aforementioned low-melting alloys are all there.

Two or three or more.

The properties of the alloy are as follows:

1. The melting point of most alloys is lower than the melting point of any of the constituent metals in their components. The electrical and thermal conductivity of the alloy is lower than that of any group of metals. Using this property of alloys, it is possible to manufacture materials with high resistance and high thermal resistance. It is also possible to manufacture materials with special properties.

2. The hardness is generally greater than the hardness of any metal in its components.

3. The electrical and thermal conductivity of the alloy is lower than that of any group of metals.

4. Some have strong corrosion resistance (such as stainless steel), such as adding 15% chromium and 9% nickel to iron to obtain a corrosion-resistant stainless steel.

The main types and properties of alloys.

There are three main cases: the first case is that the alloy does not form a solution, but is just a mixture of two metal crystals; In the second case, a solid solution is formed, that is, a solid solution; In the third case, a compound is formed.

1. Mixed alloy (eutectic mixture), when the liquid alloy solidifies, the components that make up the alloy are crystallized separately to form an alloy, such as solder, bismuth-cadmium alloy, etc.

2. Solid melt alloy, when the liquid alloy solidifies, the solid solution is formed, such as gold and silver alloys.

3. Metal interoxide alloys, alloys in which each component forms compounds with each other, such as brass (-brass, -brass and -brass) composed of copper and zinc.

The properties of alloys are that the melting point of most alloys is lower than the melting point of any of the constituent metals in their components, the hardness is generally greater than the hardness of any metal in their components, and the electrical and thermal conductivity of the alloy is lower than that of any constituent metal.

Common alloys are brass, stainless steel, and aluminum. These alloys are widely used in various fields, such as aluminum alloy can be used to make doors and windows, ships and aircraft, stainless steel can be used to make utensils, curtain walls, equipment shells, etc.; Brass can be used to make water ballast pipes, valves, and radiators.

Alloy structural steel

The smelting and processing technology of carbon structural steel are relatively simple and low-cost, so the production volume of this type of steel accounts for a large proportion of all steel villages. However, in the case of complex shape, large cross-section, good hardenability and high mechanical properties, alloy structural steel must be used.

The use of alloy structural steel to manufacture all kinds of mechanical parts, in addition to their high strength or good toughness, another important reason is that the alloy elements of the sliding brigade base man, increase the hardening ability of the steel, which is possible to make the parts in the entire section uniform, good comprehensive mechanical properties, that is, with high strength and enough toughness, so as to ensure the long-term safe use of parts.

The relationship between the properties of the alloy and the composition is that the composition of the alloy determines the properties of the alloy.

The properties of the alloy depend on three aspects:

1. Alloy composition;

2. Proportions;

3. Refining method.

Explanation: The alloy is characterized by low melting point and high hardness due to the mixing of the same molecules, the molecular filling is more sufficient, and the force between the same molecules is weakened. The doping components in some doping alloys can have a considerable impact, although small.

An alloy is a material made from a mixture of two or more metal elements, and its properties and composition are very different from that of a single metal element. The preparation methods of alloys include melting method, dissolution method, precipitation method, electrochemical method and other methods.

In conclusion, as an important material, alloy has a wide range of properties and applications. With the progress of science and technology and people's continuous pursuit of material properties, the research and application of alloys will become more and more extensive and in-depth.

In conclusion, as an important material, alloy has a wide range of properties and applications. With the continuous progress of science and technology and people's continuous pursuit of material properties, the research and application of alloy noise will become more and more extensive and in-depth.

The composition and properties of an alloy depend on the type, proportion, and preparation method of its constituent elements. In general, the hardness, strength, corrosion resistance, electrical conductivity and other properties of alloys are better than those of pure metals. For example, brass, an alloy of copper and zinc, has good processing properties and corrosion resistance, and is often used in the manufacture of utensils and decorations.

The alloy of aluminum and titanium has the characteristics of light weight and high strength, and is widely used in aerospace, automobile manufacturing and other fields.

Alloys have a wide range of applications, from pots and pans and jewelry in daily life to high-tech aerospace and electronics industries. In addition, alloys can also be classified according to their different properties and uses, such as structural steel, stainless steel, aluminum alloy, magnesium alloy, cobalt alloy, etc.

Question 1: The following table lists the composition and main properties of several common alloys, the name of nickel-chromium alloy; High-speed tool steel.

Question 2: How to memorize the main components, properties and uses of common alloys Please give specific content for suggestions.

Question 3: What are the components of allloy 20 alloy alloy alloy 20 is a nickel-based alloy containing molybdenum and copper, which has good hot and cold working properties. Alloy 20 nickel-based alloy is a corrosion-resistant alloy with many excellent properties, good resistance to oxidation and moderate reducing corrosion, excellent resistance to stress corrosion, cracking ability and good local corrosion resistance, and satisfactory corrosion resistance in many chemical process media.

Standard: ASTM B462

uns：n08020

Commonly known as alloy 20.

American Standard nickel-based alloy material.

Chemical composition: Cr 19-21%.

cu 3-4%

mn 2% max.

mo 2-3%

ni 32-38%

Question 4: Most of the metal materials in daily life belong to alloys, as shown in the table The main components and properties of some common alloys Alloys The main alloys (1) From the comparison in the table, it can be concluded that the melting point of the alloy is lower than the melting point of its constituent components, and the hardness, strength and corrosion resistance are stronger than those of its component metals, so the answer to this question is: lower melting point, higher hardness and better corrosion resistance; (2) Duralumin contains aluminum, copper, and magnesium, which are placed in a sufficient amount of hydrochloric acid, and the metallicity of aluminum and magnesium reacts with acid before hydrogen, and copper cannot react with acid after hydrogen; Therefore, the answer to this question is:

Copper, Mg+2HClTmgCl2+H2; (3) Rust conditions of metal iron: iron will rust when it comes into contact with oxygen and water at the same time; Stainless steel is formed, which changes the composition and structure of the metal; (4) a. In the order of metal activity, because the metal aluminum is before the iron and the copper is after the iron, the aluminum can react with the ferrous sulfate solution, and there is a layer of silvery-white reed slag on the surface of the aluminum, while the copper cannot react with the iron solution of the sulfate, thus proving the order of activity of the three metals: zinc, iron, copper, so a is correct; b. Since iron and copper are behind aluminum in the order of metal activity, neither copper nor iron can react with aluminum sulfate solution, which can only prove that aluminum is more active than copper and iron, but cannot compare the activity of iron and copper, so B is wrong; c. Since aluminum and iron are in front of copper in the order of metal activity, copper and ferrous sulfate solution and zinc sulfate solution cannot react, so the activity of copper can only be proved to be weaker than that of iron and aluminum, but it cannot prove the activity of iron and aluminum, so C is wrong; d. Because in the order of metal activity, iron and aluminum are in front of hydrogen, and can produce bubbles with dilute sulfuric acid, and aluminum produces bubbles quickly, and copper cannot react with dilute sulfuric acid, so D is correct; So the option is: ad