Fe—Cr—Mn（W,V）奥氏体钢的低温韧性

研究了Fe-Cr-Mn(W,V)低活性奥氏体钢的相稳定性对低温韧性的影响。结果表明,Fe-Cr-Mn(W,V)奥氏体钢存在韧－脆转变行为,应变诱发ε－马氏体和热诱发ε－马氏体的相互作用造成局部应力集中,导致粗晶粒亚稳奥氏体Fe-Cr-Mn(W,V）钢危性断理解,沿晶断裂抗力温度降低而减弱,发生沿晶断裂是高Mn钢断裂的重要特征。     

Fracture toughness of superplastic formed/diffusion bonded interfaces

The present paper is concerned with the interfacial fracture problem of bi-material interfaces of superplastic forming/diffusion bonding (SPF/DB) components. It has been known that the interfacial fracture toughness is a strong function of the mode mixture of crack tip, which is the most important characteristic of interfacial problems. Micromechanical models have been proposed to understand this trend of interfacial toughness curves, based on which a modified criterion for fracture under mixed-mode loading is advanced in this paper to predict phenomenological functional forms of toughness curves. On the ground of linear elastic fracture mechanics (LEFM), mode I and mode II interfacial fracture toughnesses of SPF/DB components formed under different processing conditions have been measured in this paper using the double cantilever beam (DCB) and end-notched flexure (ENF) specimens, respectively. It is found that, just as is the general trend of interfacial fracture toughness curves, the experimental results of mode II toughness values are much greater than those of mode I toughness values, and the fluctuation of mode II toughness values under different processing conditions is much greater than that of mode I toughness values. On the basis of the experimental results, the four basic parameters in the modified criterion are obtained and the interfacial toughness curve of Ti-50A/Ti-6Al-4V SPF/DB components is determined using the modified criterion for fracture under mixed-mode loading. Comparison between the results shows that the agreement between experiment and theory is excellent.     

Measurement of dynamic fracture toughness and failure behavior for explosive mock materials

In this work, a pre-cracked semi-circular shaped explosive simulant was loaded using a split Hopkinson pressure bar (SHPB). A high-speed camera was used to capture the deformation and fracture process of the specimen in situ. The digital images were processed using the digital image correlation (DIC) method. Next, full displacement and strain fields were obtained. The displacement vector field shows that the specimen fractured under tensile stress action. The strain field can be used to predict the crack propagation. Results show that the method of combined DIC and SHPB is effective to study the dynamic deformation and fracture behavior of explosive simulants. In addition, the specimen was loaded using a drop weight. The fracture toughness of the specimen was preliminary measured.     

超高韧性共聚丙烯性能与结构相关性研究

利用DSC、DMA、CIA和力学方法对两种乙丙共聚物的性能与形态结构的相关性进行了研究,揭示了盘锦共聚丙烯呈现超高韧性的原因     

相变增韧陶瓷压痕开裂的力学分析

在相变增韧陶瓷中，压痕裂纹形成的原因除了因压痕导致塑性区体积变化产生的残余应力外，还与应力诱发相变导致塑性区体积膨胀而产生的附加应力或称相变应力有关。传统的压痕法和压痕－强度法忽略了相变应力对压痕开裂和试样断裂的贡献，所测得相变增韧陶瓷的断裂韧性数据往往偏低。     

时效对JN1奥氏体钢超低温断裂韧度的影响

ＪＮ１ 奥氏体钢１３４８Ｋ固溶处理与９２３ 、９７３ 、１０７３Ｋ 时效５ｈ 后,４Ｋ 及７７Ｋ 断裂韧度测定结果表明,该钢有明显的时效脆化倾向。组织观察及Ｘ 射线衍射结果确认,时效脆化是Ｍ２３Ｃ６ 型碳化物沿晶界及退火孪晶界析出造成的。     

FRACTURE TOUGHNESS OF ORDERED INTERMETALLIC COMPOUNDS FROM SMALL DISKSHAPED SPECIMENS

１　ＩＮＴＲＯＤＵＣＴＩＯＮＣｏｎｖｅｎｔｉｏｎａｌｅｘｐｅｒｉｍｅｎｔａｌｍｅｔｈｏｄｓ,ｓｕｃｈａｓｔｈｅｄｏｕｂｌｅｃａｎｔｉｌｅｖｅｒｂｅａｍ,ｔｈｅｓｉｎｇｌｅｅｄｇｅｎｏｔｃｈｅｄｂｅａｍａｎｄｄｏｕｂｌｅｔｏｒｓｉｏｎｔｅｓｔｓ［１］,ｆｏｒｍｅａｓｕｒｉｎｇｔｈｅｆｒａｃｔｕｒｅｔｏｕｇｈｎｅｓｓｏｆｂｒｉｔｔｌｅａｎｄｓｅｍｉｂｒｉｔｔｌｅｍａｔｅｒｉａｌｓｐｒｏｄｕｃｅｒｅｌｉａｂｌｅｒｅｓｕｌｔｓ,ｂｕｔａｒｅｆａｉｒｌｙｍａｔｅｒｉａｌｓｉｎｔｅｎｓｉｖｅｂｅｃａｕｓ…     

含Cr13%高铬铸铁的试验研究

在试验的基础上研究了含Ｃｒ１３％的高铬铸铁的力学性能和组织特点,发现含硅量和变质处理对不同基体的高铬铸铁具有相似的影响规律;根据ＦｅＣＣｒ三元相图对Ｃｒ１３％高铬铸铁的凝固过程进行了分析,从一个新的角度揭示了铸造条件、含硅量和变质质处理对高铬铸铁性能和组织的影响机理。     

非晶态Fe_(46)Ni_(32)V_2Si_(14)B_6合金的分形断裂

测定了结构弛豫阶段退火温度ＴＲ对非晶态Ｆｅ４６Ｎｉ３２Ｖ２Ｓｉ１４　Ｂ６合金条带室温断裂韧性（Ｋｃ）的影响．ＴＲ小于２００℃时,ＫＣ大致不变,平均值约８ＭＰａｍ１／２;随着ＴＲ由２００℃增加至３５０℃,ＫＣ值逐渐下降至２ＭＰａｍ１／２;相应地断裂剖面形貌由不规则特征（分形的）逐渐变为平直的或光滑的特征．用垂直截面法测定断裂剖面裂纹轮廓线的分形维数Ｄｆ．实验结果表明,在准二维脆性断裂条件下,Ｋｃ值与分形维数增量的平方根成正比,并讨论不同结构弛豫阶段断裂特征长度ａｃ与断裂机制     

CRACK GROWTH, FRACTURE FEATURE AND RUPTURE LIFEDURING CYCLIC CREEP OF SUPERALLOY GH2132

１．ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｏｒｄｅｒｔｏｐｒｅｄｉｃｔｌｉｖｅｓｏｆｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｃｏｍｐｏｎｅｎｔｓ,ｉｔｉｓｉｍｐｏｒｔａｎｔｔｏｉｎｖｅｓｔｉｇａｔｅｃｒａｃｋｇｒｏｗｔｈｂｅｈａｖｉｏｒｏｆｍａｔｅｒｉａｌｓｕｎｄｅｒｃ...