AZ31B vs AZ61A Magnesium Alloy
Compare AZ31B and AZ61A magnesium alloy for strength, formability, extrusions, forgings, machining, finishing, and material selection.
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AZ31B or AZ61A? Start With the Magnesium Part You Need to Make
AZ31B and AZ61A are often compared as though the decision comes down to one line on a strength chart. In practice, the first question is usually simpler: what form of magnesium stock will make the part?
AZ31B is familiar territory for sheet, plate, and general-purpose wrought work. It is often a reasonable place to start when a lightweight enclosure, cover, bracket, or fabricated component needs bends or other forming operations before finish machining. Magnesium is never as forgiving as mild steel in a press brake, but AZ31B is commonly selected when formability needs to be part of the conversation.
AZ61A comes up more often on strength-driven extrusions, tubes, sections, and forgings. Its higher aluminum content can support higher strength in the right wrought product form. That can matter on a rail, support member, or profile where the wall cannot simply be made thicker. The payoff is not free. More strength does not make severe room-temperature forming easier, and it does not make an awkward extrusion die any easier to run.
The drawing usually tells the story. A broad panel with bends and modest mounting features points toward a sheet discussion. A long profile with localized machining pads points toward an extrusion discussion. A compact load-bearing shape may lead to a forging review. When a part is heavily pocketed and annual volume is low, machining from plate can still be the practical route.
This is where quotes can drift apart. One supplier may price AZ31B sheet with machining. Another may assume an AZ61A extrusion and only machine the functional faces. Neither route is wrong on its own, but they are not the same part-making plan. The final price, lead time, flatness, material utilization, and inspection approach can all change.
Corrosion protection and assembly deserve the same attention. Bare magnesium in a wet or galvanically active environment needs a defined protection strategy. Coating, drainage, fastener isolation, sealing, and any welding or post-weld stress-relief requirement should appear on the drawing or RFQ instead of being handled as a late shop-floor decision.
For a more detailed comparison of AZ31B and AZ61A chemistry, extrusion strength data, forming limits, machining, and RFQ requirements, read this AZ31B vs AZ61A magnesium alloy guide.
