大面积硅锂漂移探测器制备及其性能

制备了大面积硅锂漂移探测器,其性能为:探测器的灵敏面积123.6 cm~2;灵敏层深度2 mm;在室温和300 V反向偏压的工作条件下漏电流小于20 μA;对~(241)Am 5.486 MeV α粒子的能量分辨(FWHM)为77.67 keV。     

PC／ABS合金的研制及其在汽车上的应用

对ＰＣ／ＡＢＳ合金开发和研制及其在汽车上的应用作了评述。介绍了上海杰事公司在该领域的进展。     

AN EXPERIMENTAL INVESTIGATION OF THE GROWTH OF SMALL CORNER FATIGUE CRACKS IN ALUMINIUM 6061-T651

Results of an experimental investigation of the fatigue growth of small corner cracks emanating from small flaws are presented. Growth-arrest behaviour was observed, and increases in crack length during growth periods were of the order of the transverse grain size. For the test material, the corner crack front intersects, on average, only three–six grains in the small crack regime monitored, so only a small number of constrained, interior grains is encountered. It is suggested that the presence of partially constrained surface grains may contribute to the 'anomalous' growth behaviour which has been observed by a number of investigators.
The crack growth histories of the test data presented exhibit considerable scatter. It is shown that a Student's t -test can be used to estimate confidence intervals in order to provide a measure of the observed scatter. The variation in confidence intervals in the transition from small to long fatigue crack growth is discussed.     

烧结直接淬火对WC－TiC－Co合金WC相微观结构及力学性能的影响

本文以ＴＥＭ和ＸＲＤ为主要手段，研究ＷＣ－ＴｉＣ－Ｃｏ硬质合金（ＹＴ１４）在直接淬火后ＷＣ相的微观结构和微观应力，比较了常规烧结态与淬火态试样ＷＣ相之间的差异，探讨了直接淬火对合金力学性能的影响。结果表明，在保持合金其他性能不降低的同时，直接淬火的抗弯强度比常规烧结提高２８％左右。并首次发现，经直接淬火热处理的ＹＴＩ４合会中与Ｃｏ相相邻的ＷＣ晶粒边界出现滑移台阶，这是淬火过程中热应力使ＷＣ晶粒内位错在｛０００１｝密排面聚集，并可能沿｛０００１｝＜１１２０＞易滑移系统强滑移的结果。直接淬火试样的微观应力比重新加热淬火的低。     

铝阳极氧化膜颜色的检验和观察法

介绍铝及铝合金阳极氧化膜颜色的概念和描写,对颜色的儿种测量方法进行了比较,重点分析观察法及其在各国标准中的异同。在此基础上,提出了GB8013中的对颜色进行观察的条件和理论根据。     

CHARAC TERIZATION OF TiAl POWDER PRODUCED BY MECHANICAL ALLOYING

The microstructure,alloying reaction and sintering behavior of the powder produced by Mechanical Al-loying(MA)for 8 h from 64 wt.-% Ti powder and 36 wt.-% Al powder were studied by scanning electronmicroscopy,optical microscopy,X-ray diffractometry,differential scanning calorimetry(DSC)and dilatometry.The mechanically alloyed powder partictes are Ti-Al composite particles.Thus,titanium aluminides can formeasily in the powder through diffusion during heat treatment.It is shown that the sintering behavior of this pow-der,different from the behaviors of TiAl alloy powder and mixed powder of 64 wt.-% Ti powder and 36 wt.-%Al powder,changes from expansion at temperatures below 1000℃ to shrinkage at temperatures above 1000℃.Homogeneously alloyed TiAl material with a density over 96% of the theoretical density can be produced fromthe mechanically alloyed powder by compaction-sintering.     

Mold-filling characteristics of AZ91 magnesium alloy in the low-pressure expendable pattern casting process

The magnesium (Mg) alloy low-pressure expendable pattern casting (EPC) process is a newly developed casting technique combining the advantages of both EPC and low-pressure casting. In this article, metal filling and the effect of the flow quantity of inert gas on the filling rate in the low-pressure EPC process are investigated. The results showed that the molten Mg alloy filled the mold cavity with a convex front laminar flow and the metal-filling rate increased significantly with increasing flow quantity when flow quantity was below a critical value. However, once the flow quantity exceeded a critical value, the filling rate increased slightly. The influence of the flow quantity of inert gas on melt-filling rate reveals that the mold fill is controlled by flow quantity for a lower filling rate, and, subsequently, controlled by the evaporation of polystyrene and the evaporation products for higher metal velocity. Meanwhile, the experimental results showed that the melt-filling rate significantly affected the flow profile, and the filling procedure for the Mg alloy in the low-pressure EPC process. A slower melt-filling rate could lead to misrun defects, whereas a higher filling rate results in folds, blisters, and porosity. The optimized filling rate with Mg alloy casting is 140 to 170 mm/s in low-pressure EPC.     

大型薄壁铝铸件表面沟槽缺陷的产生及消除

针对大型薄壁铝铸件内腔表面出现的沟槽缺陷,从差压铸造、树脂砂、铸件结构等工艺条件方面探讨了产生的机理,并通过试验和对比研究,确定排气不畅是该缺陷的首要引发因素,找到了消除该缺陷的工艺方法,提出了相关预防措施,避免了因此产生的废品损失.     

Influence of initial textures on dynamic recrystallization and textures in AZ31 magnesium alloys

1　INTRODUCTIONMagnesiumisthelightestmetallicstructurema terialwithhighspecificstrengthandthereforeiswidelyusedinautomotive ,electronicsandaerospaceindustries[1,2 ] .However ,magnesiumoftenshowsinsufficientplasticityatroomtemperatureduetoitsHCPstructurewithlessindependentsystemsofbasalslip .Toenhanceformabilityofmagnesium ,ahigherdeformingtemperatureisusuallyusedwithtwopur poses .Thefirstistoactivatenewslipsystemsbesidesbasalslip ,sothatmorethanfiveindependentslipsystemscanbeprovided ,be…