NASA/TM-209876, Lee, J.A. and Carter, R.W. and Ding, J., Friction Stir Welding for Aluminum Metal Matrix Composites (MMC's), (MSFC Center Director's Discretionary Fund Final Report, Project No. 98-09), Materials Processes and Manufacturing Department, Engineering Directorate, NASA Marshall Space Flight Center, AL 35812., December 1999, pp. 28, Format(s): PDF 7810k |
This technical memorandum describes an investigation of using friction stir welding (FSW) process for joining a variety of aluminum metal matrix composites (MMC's) reinforced with discontinuous silicon-carbide (SiC) particulate and functional gradient materials. Preliminary results show that FSW is feasible to weld aluminum MMC to MMC or to aluminum-lithium 2195 if the SiC reinforcement is less than 25 percent by volume fraction. However, a softening in the heat-affected zone was observed and is known to be one of the major limiting factors for joint strength. The pin tool's material is made from a low-cost steel tool H-13 material, and the pin tool's wear was excessive such that the pin tool length has to be manually adjusted for every 5 ft of weldment. Initially, boron-carbide coating was developed for pin tools, but it did not show asignificant improvement in wear resistance. Basically, FSW is applicable mainly for butt joining of flatplates. Therefore, FSW of cylindrical articles such as a flange to a duct with practical diameters ranging from 2-5 in. must be fully demonstrated and compared with other proven MMC joining techniques for cylindrical article
| Keywords: | friction stir welding, metal matrix composites, silicon-carbide, functional gradient materials, wear-resistant coating, aluminum-lithium 2195, flanges, ducts, pin tool, joining technologies |
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| Subjects: | Chemistry and Materials: Metals and Metallic Materials: Aluminum |
| ID Code: | 504 |
| Deposited On: | 24 July 2002 |