Magnesium Alloy vs Aluminum Alloy

Is Magnesium Alloy Suitable for Powered Mobility and Human-Powered Gear?

Summary: Magnesium alloy is the optimal lightweight solution for powered mobility and human-powered gear, reducing weight by 33% compared to aluminum alloy. This article details its application scenarios, engineering requirements, trade-offs with aluminum alloy, common mistakes, and supply chain support to help you make informed material choices.

Key Takeaways

Core Advantage: Magnesium alloy is the best lightweight solution for improving the "power-to-weight ratio" of powered mobility equipment, reducing weight by 33% compared to 6061 aluminum alloy, balancing light weight and controllability.

Major Risks: Fatigue fracture under high-frequency dynamic alternating loads (fatigue limit is 60%-70% of aluminum alloy); galvanic corrosion without isolation (magnesium is prone to anodic dissolution when in contact with steel and copper).

Not Recommended Scenarios: ① Transmission core components with continuous working temperature ≥120°C (prone to creep and strength reduction); ② Unprotected water-exposed load-bearing structures without anti-corrosion treatment.

Recommended Strategy: Prioritize application in non-load-bearing structures, motor housings, and optimization of vehicle unsprung mass (1kg reduction in unsprung mass is equivalent to 5-10kg reduction in sprung mass).

The Verdict

Magnesium alloy is an inevitable upgrade from aluminum alloy for manned/human-assisted power equipment (electric scooters, E-bikes, hand-held tools, etc.). It is widely used in magnesium alloy for E-bike and magnesium alloy for electric scooter due to its unique advantages:

•          Lightweight: Reduces operational fatigue, improves work efficiency and battery life of hand-held equipment;

•          Shock Absorption: Its damping coefficient is more than 10 times that of aluminum alloy, absorbing high-frequency vibrations, reducing noise, and enhancing handling feel.

Prerequisites for Replacement (Must Meet):

•          Stress Optimization: Increase local wall thickness and arrange reinforcing ribs to compensate for the insufficient rigidity of magnesium alloy (45GPa), which is only 64% of aluminum alloy (70GPa);

•          Fastener Treatment: Direct tapping on magnesium matrix is strictly prohibited; H6 tolerance steel thread bushings + anti-loosening structures must be pre-embedded.

Engineering Quick Judgment

Recommended Scenarios

•          Personal Vehicles: E-bike motor cooling housings, electric scooter folding columns, light balance wheel hubs (magnesium alloy for E-bike motor housing is highly recommended);

•          Hand-Held Power Equipment: Chainsaw bodies, garden trimmer frames, portable impact drill housings (weight reduction directly improves work efficiency, i.e., "weight reduction = production increase");

•          Mobile Robots: Delivery robot chassis brackets and protective armor (lightweight improves battery life, shock absorption protects internal precision components).

 Conditional Requirements

•          Surface Anti-Corrosion: MAO (Micro-Arc Oxidation, an anti-corrosion process for magnesium alloy) + powder coating composite process (MAO layer 15-25μm, powder layer ≥60μm), passing 72-hour neutral salt spray test (GB/T 10125-2021);

•          Material Selection: ZK60 magnesium alloy (tensile strength ≥380MPa, yield strength ≥300MPa) for high dynamic impact parts; AZ91D semi-solid die casting (0.5mm ultra-thin wall) for complex thin-walled parts (ZK60 magnesium alloy application is ideal for high-impact scenarios).

 Not Recommended Scenarios

•          Internal Combustion Engine Direct Connection Parts: Areas with long-term working temperature ≥150°C (prone to creep and deformation failure);

•          Extreme Impact Points: Unreinforced bottom guard plates and bumpers (high notch sensitivity, prone to brittle fracture).

How to choose lightweight materials? This feasibility study analyzes four main materials on performance, costs, sustainability, case studies, and decision matrices. Click for the guide! 

1 Breakthrough in Lightweight Magnesium Alloy Bicycles

  1.1  Critical Stress Concentration Risks

  1.2  Mg Frame Recall

2. Outdoor Gear Material Application

      2.1 Root Cause of Trekking Pole System Failures

      2.2 Trekking Pole Tubing Manufacturing

3. Comparison and selection guide

    3.1  Overview of the Four Materials

    3.2 Key Performance Comparison

     3.3 From  Material to Component

     3.4 Material Cost and Supply Chain

    3.5 Application Fields

     3.6 Sustainability and Recyclability Performance

     3.7 Future Directions

     3.8 Selection Guidelines and Decision Matrix

4 Flying Car

5 Engineering Boundaries of Aluminum Alloys

6 Engineering Limits of Magnesium Alloys | AIKERLY

7 Bridging Titanium’s Engineering Divide

8 Magnesium Alloy vs Aluminum Alloy

9 Mg vs Al HPDC

10 Carbon Fiber Reinforced Magnesium Matrix (Cf/Mg) Composites