ECR PLASMA-ASSISTED DEPOSITION OF AL2O3 AND DISPERSION-STRENGTHENED ALOX

Electron cyclotron resonance (ECR) O-2 plasmas, in conjunction with el ectron-beam evaporation of Al, were used to grow thick A1O(x) films wi th varying but controlled composition and microstructure. The ion ener gy was varied from 30 to 190 eV, and growth temperatures varied from 3 5 degrees C to 400 degrees C. The ECR-film compositions were varied fr om AlO0.1 to Al2O3 by controlling the plasma parameters and Al deposit ion rate. The Al-rich alloys exhibited a fine-grain (10-100 nm) fee Al microstructure with y-Al2O3 precipitates (similar to 1 nm), similar t o those reported previously in gigapascal-strength O-implanted Al. The measured hardness of the ECR Al-O alloys (similar to 3 GPa) was also comparable to that of the ion-implanted alloys which implies that the yield strength of the ECR material is similar to 1 GPa. Moreover, the Al-O alloys retain much of the elasticity of the Al metal matrix.