Different Ingredients
Zinc is the primary alloy of 7075 aluminum alloy.
Magnesium and Silicon are the primary alloys of 6061 aluminum alloy.
| ALUMINIUM ALLOY | Si | Fe | Cu | Mn | Mg | Cr | Zn | Ti | Zr | Others | AL |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 7075 | 0.4 | 0.5 | 1.2-2.0 | 0.3 | 2.1-2.9 | 0.18-0.28 | 5.1-6.1 | 0.2 | —— | 0.15 | reminder |
| 6061 | 0.4-0.8 | 0.7 | 0.15-0.4 | 0.15 | 0.8-1.2 | 0.04-0.35 | 0.25 | 0.15 | —— | 0.15 | reminder |
✣All compositions are in percent.
From the above table, we can see that the 7075 aluminum alloy is with much higher alloys in all aspects than the 6061 aluminum alloy.
Different Strength and Hardness
The 6061 aluminum contains more aluminum than the 7075 aluminum, so its mechanical properties will be lower than 7075. More pure aluminum, softer the aluminum alloy, because pure aluminum is a tranquil metal element.
In general, we have different methods for measuring the strength of metals. There are three most commonly used methods to measure the strength of aluminum alloys. It is the measurement for Yield Strength, Shear Strength, and Tensile Strength. The following are the data of the strength measurement of aluminum alloys of 6061 and 7075:
| ALUMINIUM ALLOY | Yield Strength | Shear Strength | Tensile Strength |
| 6061 | 7KSI | 10KSI | 13KSI |
| 7075 | 15KSI | 22KSI | 33KSI |
Aluminum alloy temper, which can change the characteristics of the metal itself to become another material with entirely different mechanical properties. Also, another way to increase the overall strength of aluminum alloy is what we called “heat treatment.” Generally, the “quenching” we often hear is a kind of “heat treatment.” It is to increase the strength of the aluminum alloy after it is heated at a high temperature and then rapidly cooled.
We often see aluminum alloys treated with “T6″ heat treatment. After the T6 heat treatment of 6061, aluminum alloy can greatly enhance the Yield Strength and Tensile Strength of the aluminum alloy. And the 7075-T6 heat-treated aluminum alloy also has a large increase in Yield Strength”, Tensile Strength, and Shear Strength.
| ALUMINIUM ALLOY | TEMPER | Yield Strength | Shear Strength | Tensile Strength |
| 6061 | 7KSI | 10KSI | 13KSI | |
| 6061 | T6 | 31KSI | 17KSI | 35KSI |
| ALUMINIUM ALLOY | TEMPER | Yield Strength | Shear Strength | Tensile Strength |
| 7075 | 15KSI | 22KSI | 33KSI | |
| 7075 | T6 | 73KSI | 48KSI | 83KSI |
After the T6 heat treatment, the hardness is different. 7075T6 is a high hardness aluminium alloy, so it is tough to weld and fabricate.
| ALUMINIUM ALLOY | HARDNESS HBW |
| 6061T6 | ≥95 |
| 7075T6 | ≥150 |
Different Application And Price
7075T6 is the lightest and most durable aluminum alloy, so its price is high.
6061T6 is the most common aluminum alloy for industrial production, and It is light, durable, and economical.
7075 contains a high proportion of other metals, so welding and fabrication are all complicated. Since 6061 has a low percentage of other metals, it can increase its strength by various methods and treatments, so the application range is much more extensive. The sales and usage rate of 6061 in the market is relatively high compared to 7075. Usually, 6061 is the highest-selling industrial aluminum alloy material because its performance is consistent with various industrial applications such as machining and equipment processing. Also, the factory’s production and processing costs for the 6061 are relatively low, so the supply and usage of the 6061 are relatively large. Since the price of the 7075 is relatively high, it is generally used for aluminum alloy for aviation and aircraft.