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Introduction 1 Laser Apparatus 2 Specimen Configuration Real-Time Measurements and T^eir Limitations Temperature Measurements Strain Measurements 10 Stress Measurements Metallograph} of Uncoated Steel Samples CVD of W-Coated Steel Samples Summarv Conclusions A. Real-Time Measurements B. Response and Degradation of Target Material Pulsed-laser heating-a tool for studying degradation of materials subjected to repeated high temperature excursions* ABSTRACT We evaluated the use of pulsed-laser heating as a means to obtain high cyclic peak temperatures with short rise limes. We used a two-stage neodymium glass laser which produces a 600-^s pulse with energy outputs of up to 100 J. Small disk-shaped samples of AISI 4340 steel served as t.irgets. Some of these were coated with a tungsten deposit. The rear face of some of the targets was instrumented for evaluation of tem perature, strain, and stress response. Post-shot melallographic evaluations were made on a number of targets. We saw evidence of surface melting, cracking, and phase transformation. Surface damage was related to diffeiences in the number of pulse cycles and input energy level, variables in the target materials, and the exten' of strain-induced stresses. These ex periments were performed in air at 1 atm and ambient laboratory temperature.

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