Effect of hydrogen on martensite formation in austenitic stainless steels in high-pressure torsion

The martensitic transformation induced by high-pressure torsion (HPT) and hydrogen desorption in Type 304 and 316L austenitic stainless steels is reported in this paper. When Type 304 with only 2.2 mass ppm hydrogen was subjected to HPT, up to 95% of the austenite transformed to martensite. For Type 316L with 1.5 ppm hydrogen content, martensitic transformation during HPT was up to 50%. Martensitic transformation during HPT was suppressed by hydrogen pre-charging to <80% for Type 304 with 24.2 ppm hydrogen and <10% for Type 316L with 22.3 ppm hydrogen. This is presumed to be due to slip localization by hydrogen-enhanced slip planarity. Because of the significantly greater hydrogen solubility and lower diffusivity in austenite as compared to martensite, it is hypothesized that when hydrogen-containing austenite is transformed to martensite, excess hydrogen is released and then diffuses primarily through martensite.     

Inference of plastic deformation in weldment with parallel cracks from infrared thermography

Tensile tests are carried out by using the welded plate with two parallel cracks. The effects of the residual stress, the hardened zone by welding and the interaction between cracks on the plastic deformation near cracks and the crack opening displacement are examined by the experiment as well as the elasto plastic finite element analysis. A new technique for evaluating nondestructively the plastic deformation near cracks by using the infrared thermography is proposed. The heated region and the temperature rise measured by the thermography are compared with the plastic zone and the work of plastic deformation obtained by the analysis. The validity and the limitations of the application of the infrared thermography to the evaluation of the plastic deformation are discussed.     

Radical copolymerization of ethylene and 2-phenyl-3-vinyloxirane

The radical copolymerization of ethylene and 2-phenyl-3-vinyloxirane was carried out under high pressure to obtain the corresponding copolymers. The structure of the obtained copolymers was discussed by the data of infrared and nuclear magnetic resonance.     

Effects of Silver and Palladium Doping on the Dielectric Properties of 0.9Pb(Mg1/3Nb2/3)O3–0.1 PbTiO3 Ceramic

The doping of silver and palladium into a 0.9Pb-(Mg_1/3Nb_2/3)O₃–0.1PbTiO₃ (PMN–PT) ceramic has been investigated. It was found that Ag could be incorporated into the PMN–PT lattice, though this was almost impossible with Pd. Doping at up to 0.2 mol% of Ag and Pd reduced the maximum dielectric constant ( K _max) from 21000 to 14000 without any conspicuous change in physical properties. Order–disorder transitions in the perovskite structure contributed to the decrease in K _max, since the diffuseness parameter, δ, which represents the degree of the order-disorder relationship, increased with Ag doping. However, addition of more than 0.2 mol% increased K _max. Increases in grain size and in the perovskite ratio contributed to this increase. The dielectric properties of Ag/Pd-doped samples were intermediate between the Ag- and Pd-doped samples.