u/whocareshoo

Many people ask whether magnesium alloy can replace common aluminum alloys such as 6063 or 6061.

From a practical material-selection perspective, my view is:

If the original aluminum product uses 6063, then AZ31B magnesium alloy can often be considered as an alternative.

If the original aluminum product uses 6061, then AZ61 magnesium alloy may be a more suitable replacement option.

However, this does not mean we can simply copy the same design directly.

For example, compared with 6063 aluminum, AZ31B magnesium alloy may have comparable tensile strength in some applications, but its yield strength can be lower. So the replacement method depends on the product function.

If it is a decorative part or a non-load-bearing part, the original aluminum design may often be replaced with magnesium alloy without major structural changes.

But if it is a load-bearing product, such as a folding table, frame, bracket, or structural profile, the magnesium alloy profile may need some wall-thickness adjustment to meet the required strength.

Even when the wall thickness is increased, the final magnesium alloy product can still usually achieve weight reduction compared with aluminum. It may not always reduce weight by 30%, but a 20–25% reduction can still be valuable in many applications.

With current processing costs becoming more competitive, I think this is a good time for some aluminum alloy products to evaluate magnesium alloy replacement.

My basic view:

6063 aluminum → AZ31B magnesium alloy

6061 aluminum → AZ61 magnesium alloy

But every replacement project should be checked according to:

* load-bearing requirement

* wall thickness

* product structure

* processing method

* surface treatment

* cost target

* weight-reduction target

Magnesium alloy is not a “direct copy” replacement for aluminum, but with the right design adjustment, it can be a very practical lightweighting solution.

Would you consider magnesium alloy for aluminum replacement in your products?

Magnesium alloy parts are often misunderstood in vehicle fire discussions.

A thin magnesium strip or magnesium powder can burn easily.

A solid automotive magnesium alloy component is a very different engineering material.

More magnesium alloy parts in EVs do not automatically mean higher fire risk. Under normal automotive use and early-stage fire conditions, solid magnesium alloy components are unlikely to be the primary ignition source or the main driver of fire spread.

The real question is not “Is magnesium flammable?”

The better question is:

What alloy, what component geometry, what surface condition, what fire exposure, and what vehicle safety design?

That is how engineers should look at it.

Curious to hear from materials engineers, EV safety people, and firefighters:

Have you seen magnesium alloy components create real problems in vehicle fire scenarios, or is this mostly a public misunderstanding?