304奥氏体不锈钢离子辐照后超显微硬度和微结构变化

对304奥氏体不锈钢进行固溶处理及随后的铁离子和氦离子辐照,并对三种处理试样进行超显微硬度测量和透射电镜下微观组织的观察.结果发现,相同的辐照能量和剂量下,两种离子辐照的硬化效果和微结构有较大的差异.铁离子辐照后试样的较浅层的硬化效果更显著,氦离子辐照后试样的较深层硬化效果更高些;铁离子辐照后试样表层辐照缺陷主要由高密度位错和位错缠结构成,氦离子辐照后表层辐照缺陷主要由细小致密的黑斑构成.     

用多官能团单体敏化氯化丁基橡胶的辐射交联反应

观察到丁基橡胶这一典型辐射降解型高聚物的氯化产物在电子束辐照下能发生交联反应，测得其凝胶化剂量为３．８ｋＧｙ。考究了６种多官能团单体对ＣＩＩＲ的敏化效应，以期在低剂量下达到较高的交联程度；发现三羟甲基丙烷三甲基丙烯酸酯能够有癣地提高ＣＩＩＲ的凝胶含量和交联密度。添加ＴＭＰＴ的ＣＩＩＲ经辐照后其拉伸强度几乎随ＴＭＰＴ含量成正比地线性提高。     

激光扫描速度对40Cr钢表面组织结构的影响

对调质态的４０Ｃｒ钢试样用ＣＯ２连续波输出激光速进行相变硬化处理，用穆斯堡尔谱学方法研究了激光扫描速度对试样表面层组织结构的影响，结果表明，４０Ｃｒ钢激光硬化层的组织为马氏体，残余奥氏体和少量未溶碳化物。随激光扫描速度增大，试样中的马氏体和未溶碳化物的含量不断增加，残余奥氏体含量则连续下降。     

液晶共聚酯与改性聚苯醚共混物的抗冲破坏行为及断面形态

改性聚苯醚（ＰＰＯ）和热致性液晶（ＬＣＰ）以不同的配比共混，用注射成型法加工成试样，研究了这些共混试样的落重抗冲行为，测定了临界应变能释放速度ＣＩＣ，讨论了它与液晶含量的依赖关系，并从试样形态的角度来进行解释。     

HL—1装置中的TiC涂层辐照实验研究

利用ＨＬ－１装置的等离子体辐照研究了石墨基体上的ＴｉＣ涂层。对辐照前、后 的样品进行了俄歇电子能谱（ＡＥＳ）、扫描电镜（ＳＥＭ）和Ｘ射线衍射谱（ＸＤＳ）分析，得 出：ＴｉＣ涂层内Ｔｉ、Ｃ分布比较均匀；在高功率托卡马克放电辐照下，化学腐蚀现象 较为严重，但没有改变ＴｉＣ结构相（立方ＴｉＣ）；并有一定的择优取向。同时还发现 Ｃ的优先溅射作用及 Ｔｉ向石墨基体深层扩展现象。     

强流脉冲离子束辐照316L不锈钢蠕变性能的实验研究

利用强流脉冲离子束(HIPIB)对316L不锈钢进行了表面辐照处理.辐照参数为:离子种类包括70%C 和30%H ,离子能量E=300keV,束流密度J=100,200,300A/cm2,辐照次数N=10,脉冲宽度τ=75ns,真空室本底真空度为10-3Pa.采用扫描电子显微镜(SEM)观察辐照前后试样的表面形貌;用X射线衍射(XRD)分析辐照前后试样表面层结构和成分的变化.结果表明,HIPIB辐照使试样表面光滑化,且表面层产生择优取向.研究了HIPIB辐照对316L不锈钢700℃蠕变性能的影响,发现辐照后试样的蠕变行为与束流密度密切相关.当束流密度为100,200A/cm2时,HIPIB辐照延长了原始试样的蠕变寿命;相反,300A/cm2的HIPIB辐照则使其缩短.     

紫外光辐照对超高分子量聚乙烯纤维结构与性能的影响

选用2种紫外光源,以二苯甲酮(BP)为光敏剂进行超高分子量聚乙烯(UHMWPE)纤维的表面光交联反应;采用凝胶含量测定、差示扫描量热仪分析及力学性能测试等方法,研究了辐照时间对UHMWPE纤维结构与性能的影响。结果表明,随辐照时间延长,纤维凝胶含量增加,结晶度和常规力学性能略有下降,低压汞灯和高压汞灯分别辐照20 min和10 min后UHMWPE纤维长期抗蠕变性能得到明显改善。其中,低压汞灯辐照20 min时,纤维恒定蠕变速率和强度分别为原纤维的67%和93%,性能优于相同辐照时间的高压汞灯试样。     

γ射线辐照对类金刚石薄膜结构与特性的影响

用射频等离子体方法在玻璃基底上制备了类金刚石薄膜。分析了γ射线辐照类金刚石薄膜（以下简称ＤＬＣ薄膜）的结构与特性改变。采用Ｒａｍａｎ及红外光谱进行结构分析表明：随辐照剂量的增加，在膜中出现ＳＰ３Ｃ—Ｈ及 ＳＰ２Ｃ—Ｈ 键的断裂与减少，ＳＰ３Ｃ—Ｃ键的略微增加．当辐照剂量达 １０ ×１０４Ｇｙ时，ＳＰ３Ｃ—Ｈ键减少约５０％，与此同时，出现膜中氢的重新键合，并从中释出。γ射线辐照使ＤＬＣ薄膜的电阻率呈上升趋势，膜的类金刚石特征更加明显，结构得到改善。本文对γ射线对ＤＬＣ薄膜的辐照机制进行了简要的讨论。     

MgO,CaO,Y2O3掺杂ZrO2相组成的定量分析

以共沉淀法制备了掺杂８ｍｏｌ％ＭｇＯ，ＣａＯ，Ｙ２Ｏ３的ＺｒＯ２粉料，在１５５０℃烧结得到致密的稳定或稳定ＺｒＯ２试样，应用Ｘ射线步长扫描衍射数据和Ｒｉｅｔｖｅｌｄ方法对试样进行了相含量的定量分析，结果表明，相同组份不同金属氧化物稳定的ＺｒＯ２试样在烧结后得到不同的相组成，ＭｇＯ部分稳定ＺｒＯ２为立方、四方和单斜三相混合物（１７：５７：２６：ｗｔ％），ＣａＯ的部分稳定ＺｒＯ２仅包含立方和单斜相（６     

激光辐照制备搪瓷涂层

激光辐照制备的热衷瓷涂层表面粗糙，与金属基材结合牢固，一般由Ｓｉ，Ａｌ，Ｎａ，Ｋ，Ｂ，Ｆ，Ｏ等元素组成，在激光辐照过程中Ｋ，Ｎａ明显地挥发，从而在涂层中的含量明显减少，Ｃｏ，Ｎｉ主要分布在界面附近：Ｆｅ元素也由基材进入涂层，呈梯度状分布，在界面过渡区含量很高，在涂层内含量很低，搪瓷涂层的形成与激光辐照参数，特别与激光功率间存在极为密切的关系，只有选用合理的参数，才能制得搪瓷涂层。     

激光热处理对1Cr5Mo钢焊接接头组织结构的影响

利用CO_2激光对1Cr5Mo耐热钢焊接接头进行表面热处理,通过4XC型光学显微镜对激光热处理前后焊接接头各区显微组织和晶粒度等级进行分析,并采用X射线应力仪测定激光热处理前后焊接接头残余应力和残余奥氏体的分布规律。结果表明:经激光热处理后1Cr5Mo耐热钢焊接接头表面晶粒发生细化,焊缝区、熔合区、过热区和正火区晶粒等级由9级、9.8级、8级和10.7级提升至10级、10.2级、8.5级和11级,组织结构薄弱区域由过热区、焊缝区和熔合区减少为过热区,均匀性得到了明显改善;激光热处理消除了焊接接头表面残余拉应力,形成了深度约为0.28mm的残余压应力层,残余奥氏体含量有所提高,分布更均匀,有利于改善其力学性能。     

Surface Modification of 304 Steel Using Triple-Step Shot Peening

This paper reports the influences of triple-step shot peening (SP) on the microstructure and residual stress evolution for the 304 stainless steel. The microstructure and residual stress were characterized by X-ray diffraction analysis methodology. After triple-step SP, the domain sizes decreased while the dislocation density and compressive residual stress increased as a result of the austenite and martensite in the peening deformed layer. With an increase in depth, the micro-strain for austenite decreased gradually while the micro-strain for martensite increased first, and then decreased.     

Martensitic Transformation and Residual Stress Generation During Thermomechanical Treatment

The influence of thermomechanical deformation on the residual stresses caused by quenching in bar shaped specimens of heat treatable steel SAE 4140 has been investigated using a mechanical method for determining the distribution of residual stresses of the first kind. The results obtained show that the residual stress distribution after quenching is affected by the strengthening and softening of the austenite and the modified transformation behavior in martensite stage. An attempt is made to discuss qualitatively the influence of these changes on the generation of residual stresses as compared to results obtained after conventional hardening.     

快凝M_2＋0．5B高速钢的组织与性能研究

对快凝Ｍ２＋０．５Ｂ高速钢作为刀具材料时所必须具有的性能进行了测试；借助于光学显微镜、电子显微镜、Ｘ－射线衍射仪等仪器对材料的组织和相进行了较全面的观察和分析；同时测定了淬火回火后的残余奥氏体含量，将以上各结果加以综合并进行了全面的分析和讨论。     

强化处理对GCr15钢球残余应力和微观组织的影响

实验研究了强化处理后钢球残余应力和微观组织的改变.本文研究了经强化处理后,钢球沿径向表面残余应力大小、残余奥氏体含量及硬度分布;用光学显微镜、扫描电子显微镜对经表面形变强化后的轴承钢球进行显微组织及裂纹观察.研究表明:轴承钢球次表层残余应力为压应力,随电解抛光深度的增加,逐渐会出现一个最大压应力的峰值,而后压应力值逐渐减小.强化处理过程中会发生应力诱发残余奥氏体转变为马氏体,但对压应力分布影响不大.将静态Herzt接触理论应用于钢球的动态碰撞强化中,分析探讨钢球裂纹的形成,与实验结果相一致,具有重要指导意义.     

Evaluation of changes in X-ray elastic constants and residual stress as a function of cold rolling of austenitic steels

Abstract

Austenitic steels rapidly attain high mechanical strength when subjected to cold working. The heterogeneous plastic deformation produced in cross section of the specimen, development of preferred orientation and martensitic transformation contribute to the occurrence of residual stress in cold worked steels. AISI 304 and 316 steels were cold rolled at room temperature from 10% up to 70% deformations in steps of 10%. The formation and sigmoidal growth of martensite caused by cold rolling (CR) 304 steel was studied by X-ray diffraction. The residual stresses generated were evaluated in both the austenite and martensite phases using sin² ψ technique. The accurate determination of residual stress by X-ray diffraction requires experimental determination of X-ray elastic constants for both the austenite and martensite phases. The changes in X-ray elastic constants as a function of CR of 304 and 316 steels were measured and their effect on residual stress values was established. The results show that tensile stress was generated initially on cold working in the austenite phase in both steels and in the dominant martensite phase in 304 steel, which decreases, passes through zero and becomes compressive at higher deformations. X-ray elastic constants were found to decrease in all cases and a maximum reduction of 15% was found.     

再制造大型热轧支承辊的堆焊层开裂失效分析

针对再制造大型热轧支承辊堆焊层的服役早期开裂现象,通过检测分析堆焊层硬度、显微组织和断口形貌,确定堆焊层开裂失效机制是低周接触疲劳破坏.由于堆焊层内残余奥氏体含量过多,马氏体相含量相对不足,堆焊金属低硬度、低强度,降低了再制造热轧支承辊面堆焊层的抗接触疲劳性能.通过高温回火热处理促使堆焊层残余奥氏体向马氏体转变,调控辊...     

The reverse transformations in a high-strength high-hardenability Fe-C-Si-Mn-Mo steel

The kinetics of the reverse transformations from a mixture of bainitic ferrite and residual austenite to austenite have been investigated in a steel containing a relatively high silicon concentration. It was found that the reaustenitization process was initially rapid but slow at the end of reaction and the extent of austenite formed increased with increasing reaustenitization temperature until all of the bainitic ferrite had been transformed to austenite. The process of reaustenitization was followed by dilatometry, optical and transmission electron microscopy, and stereology. The results suggested that the formation of austenite took place by the movement of planar ferrite/austenite interfaces.     

激光相变硬化残余应力研究

本文主要采用X射线法对激光相变硬化处理后试样表面至内部的残余应力进行逐层测定。并辅以小孔应力释放法予以比较。结果表明:在通常激光相变硬化处理参数下,碳钢的残余应力按正弦波规津分布。表面为压应力,内部为拉应力。其幅值随激光参数减小而减小。二次激光相变硬化处理的残余应力为拉应力。本文对残余应力在激光相变硬化处理热循环过程中的形成进行了解释。在最初升温阶段,表面发生热塑性变形而形成少量压应变。在随后的冷却过程中产生拉应变。当发生奥氏体向马氏体组织转变时,又产生压应变。因此,最终残余应力状态是表面达到的温度,塑性屈服量,组织转变量等因素综合影响的结果。而与是终形成的组织,残余奥氏体量等没有对应关系。