ENVIRONMENTAL STRENGTH OF TRIP STEELS WITH RETAINED AUSTENITE POSSESSING HIGH DUCTILITY AND HYDROGEN-EMBRITTLEMENT RESISTANCE.

采用小试样试验技术（SSTT）对残余奥氏体相变诱发塑性的高强度板材、马氏体和奥氏体钢以及激光焊接接头进行了小型化试样试验，以评价其韧性-脆性转变行为和抗氢脆性能，并与氢脆敏感性高的金属间化合物进行了比较。采用10 × 10 × 0.5 mm的小试样进行小冲孔（SP）试验，结果表明，两种残余奥氏体TRIP钢的韧性-脆性转变、低温延展性和随温度变化的威布尔分布形状参数和SP断裂能弥散存在差异。采用0.7、1.0、1.0 mm^2方形和20mm长v形缺口微型化试样，成功地进行了激光焊接接头局部组织韧性评价的冲击试验，并阐明了标准charpy冲击试验和小试样试验测量的DBTT值之间的线性相关关系。经调质热处理后，加入Si和Ni，大大提高了预应力混凝土钢的抗氢脆性能。在室温以下和室温以上，氢致敏316型不锈钢的延性损失分别伴随着沿晶界的脆性晶间开裂和增强的延性断裂。增感型316 SS对氢脆的高敏感性归因于晶界析出现象，如碳化物与基体界面结合减弱和晶界附近贫铬区马氏体转变。采用SP测试、电化学测量和氚射线自显影等方法研究了Co_3Ti金属间化合物氢环境脆的行为及其抑制作用。铁的加入抑制机理是由于氢复合的增强，氢的解吸速率增加，从而减少了Co_3Ti表面向内部的氢供应。少

The small specimen test technique (SSTT) using miniaturized specimens has been performed for high strength sheets of retained-austenite transformation induced plasticity, martensitic and austenitic steels and laser weld joint to evaluate ductile-brittle transition behavior and hydrogen embrittlement resistance, in comparison with the intermetallics having high susceptibility to hydrogen embrittlement. The small punch (SP) test using a small specimen in the form of 10 x 1 0 x 0.5 mm demonstrated different behavior of ductile-brittle transition, low lemperature ductility and the temperature-dependence Weibull distribution shape parameter and dispersion in SP fracture energies, for two different contents of retained austenitic TRIP steels. An impact testing for the toughness evaluation of local microstructures in laser weld joint using miniaturized v-notch specimens of 0.7,1.0,1.0 mm^2 in square and 20 mm in long has been successfully constructed and a linear correlation between the DBTT … More measured by standard Charpy-impact test and that by the small specimen test has been clarified.The resistance to hydrogen embrittlement of prestressed concrete steels has been largely improved by the addition of Si and Ni with quench-tempered heat treatment. The hydrogen induced ductility loss in the sensitized Type 316 stainless steels has been accompanied by the brittle intergranular cracking and enhanced ductile rapture along grain boundaries at below and above room temperature, respectively. High susceptibility to hydrogen embrittlement in the sensitized Type 316 SS has been attributed to the grain boundary precipitation relating phenomena such as the weakening of interface bonding between carbides and matrix and the martensitic transformation in the Cr-depleted zone near grain boundaries. Behavior and suppression of hydrogen environmental embrittlement in Co_3Ti intermetallic compound have been inbestigated by means of the SP test, electrochemical measurements and tritium autoradiography. The mechanism of the suppression by the additionof Fe is to reduce a supply of hydrogen from the surface to the interior of Co_3Ti due to the increase of hydrogen desorption rate resulting from the enhancement of hydrogen recombination. Less