Aluminum 6061 vs 7075: Which Alloy for Your Part

Aluminum is the most common CNC material on the platform, and most aluminum parts use one of two alloys: 6061-T6 or 7075-T6. Both appear in the quote editor for CNC machining. This article explains the practical differences so you can pick the right one before you order.

What the alloys are

6061 is alloyed mainly with magnesium and silicon. It is the general-purpose aluminum used across most industries: moderate strength, good corrosion resistance, and it welds well.

7075 is alloyed mainly with zinc, plus smaller amounts of magnesium and copper. It was developed for aerospace and has a much higher strength-to-weight ratio.

Property	6061-T6	7075-T6
Tensile strength	~45,000 psi (~310 MPa)	~83,000 psi (~570 MPa)
Yield strength	~40,000 psi (~275 MPa)	~73,000 psi (~500 MPa)

By these measures, 7075 is roughly 80 to 90 percent stronger than 6061.

Machinability and cost

6061 is one of the easiest aluminum alloys to machine. It cuts cleanly, tool wear is low, and it holds tight tolerances without difficulty, so shops can run it fast.

7075 is harder and more abrasive. It still machines well compared to steel or titanium, but cutting speeds drop, tool wear rises, and cycle times get longer.

Raw 7075 stock typically costs 30 to 60 percent more than 6061. Add the extra machining time and a finished 7075 part commonly costs 30 to 70 percent more than the same part in 6061, depending on geometry and tolerances. The exact difference for your part is visible in the editor: switch the material dropdown and compare unit prices.

Other practical differences

Fatigue. 7075 generally performs better under repeated cyclic loading, which matters for parts that flex or vibrate over a long service life.

Corrosion. 6061 has good natural corrosion resistance. 7075 is more susceptible to stress corrosion cracking, especially in parts with high residual stress or in wet or chemical environments. Proper heat treatment and coatings manage this, but it is a real consideration.

Welding. 6061 welds well with standard methods. 7075 is difficult to weld and is not recommended for welded assemblies. If the design requires welding, pick 6061 regardless of strength.

Finishing. Both alloys can be anodized, but 6061 anodizes with consistent, predictable color, which is why it dominates cosmetic parts. 7075’s higher alloy content can produce a slightly less uniform finish, and hardcoat anodizing needs tighter process control to stay consistent. Keep in mind that anodizing and other coatings add thickness, so they affect final dimensions. See Anodizing and Tolerances Explained.

Use 6061 when

• Brackets, mounts, frames, and fixtures
• Enclosures and housings
• Parts that will be welded or joined to other aluminum components
• Prototypes where cost and turnaround matter more than maximum strength

Use 7075 when

• Aerospace and drone structural components
• Gears and load-bearing mechanical parts
• High-stress fixtures and tooling
• Parts where every gram matters and strength cannot be compromised

Bottom line

The decision usually comes down to one question: does the part need strength that 6061 cannot deliver at an acceptable size and weight? If yes, 7075 is worth the premium. If the part will hold up fine in 6061, there is little reason to pay more. Start with 6061 as the default and only move to 7075 when the strength requirement demands it. You can price both alloys on the same uploaded STEP file in the quote editor to see the real cost difference before you commit.