The microstructures and mechanical properties of a family of sputter-deposited Cu 1Ϫx Ta x (0 Ͻ x Ͻ 0.18) alloys have been investigated. The as-deposited microstructures for all film compositions consisted of a polycrystalline, face-centered-cubic (fcc) Cu matrix, with varying levels of Ta in solid solution, plus a very high density of discrete, 1 to 3 nm, fcc Ta particles. Decreased deposition temperature (Ϫ120 ЊC vs 100 ЊC) increased the level of Ta in solid solution. After annealing (900 ЊC for 1 hour) the as-deposited 6 at. pct Ta films, the Cu matrix grains remained submicron and the Ta particles remained fcc with no apparent particle coarsening. Additionally, the fcc Ta particles were found before and after annealing to be oriented identically with the Cu matrix and aligned on {111} and {100} habit planes. Annealing 17 at. pct Ta films at 900 ЊC for 1 hour resulted in the formation of body-centered-cubic (bcc) Ta particles (Ͼ50-nm diameter) in addition to the much smaller fcc Ta particles. Annealing the low and high Ta composition films at 900 ЊC for as long as 100 hours produced no observed change in either the Cu matrix grain size or the size and distribution of the fcc and bcc Ta particles. Microhardness and nanoindentation mechanical property evaluations of bulk hot-pressed materials indicated that the high strengths of the composites were unchanged, even after annealing for 100 hours at 900 ЊC.

This paper develops the statistical error analysis model for assembling, to derive measures of controlling the geometric variations in assembly with multiple assembly stations, and to provide a statistical tolerance prediction/distribution toolkit integrated with CAD system for responding quickly to market opportunities with reduced manufacturing costs and improved quality. First the homogeneous transformation is used to describe the location and orientation of assembly features, parts and other related surfaces. The desired location and orientation, and the related fixturing configuration (including locator position and orientation) are automatically extracted from CAD models. The location and orientation errors are represented with differential transformations. The statistical error prediction model is formulated and the related algorithms integrated with the CAD system so that the complex geometric information can be directly accessed. In the prediction model, the manufacturing process (joining) error, induced by heat deformation in welding, is taken into account.

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In automotive manufacturing, the lack of nondestructivc methods for assessment of spot weld integrity has been a critical shortcoming, with cnormous economic consequences for both domestic and foreign automakers. At present. auto body welds are subjectively evaluated usmg destructive pull tests, or visual examination after the weld has been mechanically separated using an impact tool. Pulsed thermographic evaluation of spot welds offers a fast (K I see). noncontact method for quantitative assessment of the weld nugget. The technique can be applied using either one or both faces of the weld. Results on steel resistance welds will be presented. along u ith correlation to weld process parameters.

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