| Along with the fast progressing of the industrial technology, people concerned about the capability of automobile and aeroplane very much. Reducing frame weight is the most important method to enhance the capability. So, the demand of applying light-duty magnesium alloy becomes even more and imminence.Friction stir welding(FSW) used in our paper is a late-model solid phase welding method, which can avoid the problems existing in the other welding methods. It's an efficient, energy saving, simple and environment-friendly technique, which can efficiently avoid oxidation and evaporation without heat flaw in the cooling process after welding. FSW can get optimized various performance of joint without any sparkle, splash , smog or arc. No filling metal is needed in the welding process.In this section, we use metalloscope, SEM and micro-rigidity to test the magnesium alloy(MB3) joint during friction stir welding process. We can learn form the testing result that crystalloid is minuted and structure is compacted. If proper technique was adopted, the appearance of small openings and groove on the welding seam surface can be avoided. The co-effect of machining work-hardening and recrystal anneal makes the micro hardness fluctuant a little. And the amplitude value is close to raw material.We use mechanics testing method like stretch and bend to test the 3mm magnesium alloy(MB3) after friction stir welding. The stretch sample can show no less than 70% of raw material's performance when the condition is suitable: R= 1500r/min,v = 90mm/min,R/v=16.7 and F=1470N. Curve intensity of the joint reaches 90.2% and 83.0% at obverse and inverse curve separately.The efficient join problem of magnesium alloy was successfully solved via this technique. It do provide a necessary technique support for widely use of magnesium alloy.
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