[en] Dissipated heat has been measured by thermographic technique during fatigue experiments on Ti-6Al-4V. Surface temperature of the specimen was found sensitive to the amount of fatigue damage accumulated in the material. An increased heat dissipation due to fatigue can be related to continuous change in the microstructure (increased dislocation density, stacking faults, etc.) of the material. A method based on passive thermography can be proposed to monitor damage accumulation in Ti-6Al-4V due to cyclic loading

[en] A method is described for detecting welding seam defects during radiographic testing with an image information being obtained which then is fed into an evaluation unit for automatic defect detection or determination of the size and depth of a defect using video equipment

[en] The symposium, Nondestructive Methods for Materials Characterization, was held at the Materials Research Society 1999 Fall Meeting on November 29--30 in Boston, Massachusetts. The papers focused on advanced nondestructive evaluation (NDE) methodologies and instrumentation. Several X-ray techniques were developed or tailored for process control and deformation behavior in high- and low-density materials. Fracture, fatigue, and corrosion behavior of aging aircraft materials were characterized via linear and nonlinear acoustics. Structure-sensitive properties in magnetic materials and building materials were gauged with NDE parameters. Electric and dielectric properties in ceramics and composite materials were established. Thickness and interface properties in silicon wafers and thin films were studied. Advanced optical and infrared techniques were investigated for the characterization of capacitance, circuit boards, laser diodes, and material growth. Thirty five papers were processed separately for inclusion on the data base

[en] On the basis of the safety-technical requirements of the nondestructive testing of pressurized components in power plants, the methods of monitoring or the in-operation testing of the material integrity are discussed. Besides the classical fault tests, these are mostly processes which react sensitively to micro-structural alterations of the materials. The state of development of the methods is critically evaluated and a preview is given of the direction, in which new knowledge development and research in this field can be expected. (author) 44 figs., 5 tabs., refs

[en] The peak counting rate of the angular correlation curve was measured for Cu and Au in the temperature range between -196⁰C and 1,200⁰C. The experimental data were analysed by means of the trapping model under consideration of positron trapping by mono- and divacancies and detrapping of positrons from monovacancies. Such an analysis leads to acceptable results for both monovacancy and divacancy parameters. (orig.)

[en] Recently some effects of the study of vacancies by means of positron annihilation which might cause systematical errors were discussed. One of them is the positron trapping by multiple vacancies near the melting point. To study this problem the temperature dependences of the peak height H for Al, Cu, and Ni have been measured. For Al and Cu the behaviour of H near the melting point is explained in detail. For Ni the estimation of the formation energy of monovacancies is discussed mainly. The investigations show that the data of positron annihilation in metals near the melting point must be analysed under consideration of positron trapping by monovacancies as well as by divacancies. For high melting metals detrapping of positrons from monovacancies becomes important leading to an enhancement of the positron trapping by divacancies

[en] The recovery and recrystallisation behaviour of cold rolled Ni of differing purity, such as Ni doped with Sb, Ti and B, between room temperature and 550⁰C was studied by measurement of the peak counting rate of 2γ-angular correlation during annealing with constant heating rate. The results indicate a strong dependence of the annealing behaviour on type and concentration of impurity atoms. For Ni of purity 99.8% and especially for NiSb the peak counting rate shows a large increment in the temperature region 200 to 400⁰C which it is suggested is caused by the formation of vacancy clusters. (author)

[en] Estimation of the enthalpy Hsub(vi)sup(B) for the binding of a monovacancy and a single Sb impurity in the Ni matrix was done by measurement of the peak hight of the 2γ angular correlation curve. Samples were prepared form pure Ni alloyed with 390 at ppm Sb and with 350 at ppm Sb + 200 at ppm B. Wires of the sample material has been irradiated with thermal neutrons in order to produce an internal positron source of about 20 mCi ⁵⁸Co

No abstract available

[en] Proceeding from the physical fundamentals of the electron microprobe analysis, a commercially available analyzer is described. The possibilities of qualitative and quantitative analyses are demonstrated on the basis of soldered joints