STRESS AND ENERGY TRANSFER OF WATER COUPLING BLASTING

ＳＴＲＥＳＳＡＮＤＥＮＥＲＧＹＴＲＡＮＳＦＥＲＯＦＷＡＴＥＲＣＯＵＰＬＩＮＧＢＬＡＳＴＩＮＧ①ＺｈａｎｇＱｉａｎｇＢｅｉｊｉｎｇＧｅｎｅｒａｌＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＭｉｎｉｎｇ＆Ｍｅｔａｌｕｒｇｙ，Ｂｅｉｊｉｎｇ１０００４４，Ｐ．Ｒ．...     

Cap rock blast caving of cavity under open pit bench

A laser technique based scanning system was employed to make a comprehensive scanning through borehole for unmapped cavity under open pit bench, then the three-dimensional data will be obtained, and these data were used for theoretical analysis and numerical simulation to analyze the stability of cap rock. Acoustic emission techniques were also adopted to carry out long term real time rupture monitoring in cap rock. Therefore, a complete safety evaluation system for the cap rock was established to ensure safe operation of subsequent blasting processes. The ideal way of eliminating collapse hazard of such cavity is cap rock caving through deep-hole blasting, thus, two deep-hole blasting schemes named as vertical deep-hole blasting scheme and one-time raise driving integrated with deep-hole bench blasting scheme were proposed. The vertical deep-hole blasting scheme has more explosive consumption, but the relatively simple blasting net work structure can greatly reduce workloads. However, the one-time raise driving integrated with deep-hole bench blasting scheme can obviously reduce explosive consumption, but the higher technical requirements on drilling, explosive charging and blasting network will increase workloads.     

Monel合金/Cu爆炸复合棒界面的微观组织和力学性能

利用爆炸复合的方法成功制备了Monel合金/Cu双金属复合棒材.借助金相显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)和压剪分离测试,探讨了不同工艺条件下Monel/Cu爆炸复合界面的微观组织和力学性能.结果表明,随着爆炸比的增加,结合界面逐渐由平直状过渡到波状;在铜基体晶粒内的形变孪晶数量随爆炸比的增加而增加;界面局部存在少量熔区,熔区内存在细小的柱状晶;复合界面中没有发生扩散,但经过热处理后其界面观察到了扩散.剪切断裂发生在铜侧而非界面处,表明界面结合强度高于铜基体.     

圆筒内嵌钨合金球爆炸加载条件下断裂机制研究

针对钨合金作为预制破片战斗部穿甲后的易碎性,采用圆筒内嵌钨合金球战斗部,研究了97.5W-Ni-Fe合金在圆筒内嵌式爆炸加载穿靶前后的微观组织以及断裂机制。结果表明,97.5W-Ni-Fe合金爆炸加载后在钨颗粒内部产生大量形变孪晶,穿透靶板后形变孪晶诱发大量微观裂纹,微裂纹在穿靶后的拉应力作用下扩展并与W-W界面断裂相互连接,使钨合金球断裂成有效破片,增强了钨合金的二次毁伤能力。     

爆炸加载下钨合金的断裂特性SCIEI

用微量炸药接触爆炸的方法，研究了钨合金９３Ｗ─４Ｎｉ─３Ｆｅ在高加载率条件下的断裂特性，通过宏、微观观察，以及与静态断裂特性相比较，发现随着加载率的增加，钨─钨界面裂纹增加，致使钨合金的断口呈脆性状态。     

Laser texturing as an alternative to grit blasting for improved coating adhesion on AZ91D magnesium alloy

Substrate preparation plays an important role in the performance of thermal spray coating, especially on softer materials like magnesium and aluminium alloys. Conventional substrate preparation methods such as grit blasting may not be the most suitable choice due to grit embedding, lower coating adhesion strength and environmental concerns. Laser texturing can be an attractive alternative to the grit blasting method for such materials. AZ91D substrate was prepared for thermal spray coating using grit blasting and laser texturing techniques. WC-12Co powder was thermally sprayed on AZ91D magnesium alloy using the high-velocity oxygen fuel technique. The adhesion strength of the coating, thus produced, was determined using the ASTM 633C adhesion strength test. Scanning electron microscopy was used to investigate substrate morphology and to qualitatively analyse substrate and coating interface. X-ray diffraction was used to identify phase compositions. The coating was characterised for roughness, porosity, micro-hardness and fracture toughness. Laser texturing as a substrate preparation technique has been able to produce well-adhered coatings, with adhesion strength of 45.6?MPa, and comparable coating characteristics with those of the grit blasting technique.     

钛/钢爆炸复合板界面连接机理与力学行为

本文表征了钛/钢爆炸焊接复合板的界面组织和剪切性能,研究爆炸复合过程的界面结合机理。结果表明,在金属板之间形成了波状界面组织,剧烈塑性变形造成钢基体发生明显的塑性流动,并在界面形成连续的漩涡形貌。TEM和XRD检测证实界面存在纳米尺度的过渡层,并包含有固溶体组织和少量金属间化合物。波状界面组织改善了复合板沿爆炸方向的界面剪切强度,剪切断口显示漩涡组织发生韧性断裂形貌。     

高应变率下铀铌合金的断裂组织特征

对经过内部爆破加载后产生的U-Nb合金破片进行了断口形貌、金相组织等微观分析。结果表明：U-Nb合金在爆炸加载下的断裂方式为剪切断裂；破片组织内部发现因高速应变引起的大量的绝热剪切带，靠近绝热剪切带的基体晶粒发生明显的拉长变形：破片中存在大量的微裂纹，裂纹沿着绝热剪切带扩展，当与沿壳体环向的拉应力形成的纵向主裂纹相交汇时，形成破片。     

Fatigue behavior of a SAE 1045 steel coated with Colmonoy 88 alloy deposited by HVOF thermal spray

An investigation has been conducted in order to study the fatigue behavior of a SAE 1045 steel substrate coated with a Ni-base alloy known commercially as Colmonoy 88, deposited by HVOF spray technique. Fatigue tests were conducted under axial conditions (R = 0.1), employing samples of the substrate material in the as-polished condition, after grit blasting with alumina particles and after grit blasting and coating with a deposit of about 250 μm thick. The fatigue tests were conducted at maximum stresses in the range of 380-533 MPa, depending on the condition of the material. A detailed fractographic analysis of some selected samples tested at different stresses was carried out, aimed mainly at determining the crack nucleation and propagation sequence. The results indicate that the deposition of such a coating leads to a fatigue strength debit of the substrate in the range of 10-20% and a similar debit in fatigue limit of ∼ 11-13%. It has been found that grit blasting is the process responsible for the fatigue strength debit observed in the coated samples. Fatigue cracks have been observed to initiate at the substrate-coating interface and at the free surface of the coating, mainly close to alumina particles embedded on the substrate and sharp notches produced during the process. The fractographic analysis of the fracture surface of the coated specimens points out the characteristic heterogeneous nature of the coating, particularly regarding some of its mechanical properties, such as fracture toughness.     

爆炸压涂钨铜覆层到铜表面的研究

采用爆炸烧结将钨铜合金覆层烧结到纯铜表面的方法,即将钨铜合金粉末预压到铜板的表面后,进行通氢烧结,然后通过爆炸压实将混合粉末进一步压实在铜板表面,最后扩散烧结成为钨铜复合材料。先采用AUTODYN软件模拟了爆炸压实过程中粉末与铜板中的压力分布,确定了一套可以使覆层粉末中压力分布均匀,有利于钨铜合金粉末均匀致密化的参数。而后进行爆炸压实试验,制出的试样覆层密度达到了理论密度的99.3%。对爆炸后的试件进行电子探针检测,检测结果表明钨铜粉混合均匀,钨颗粒的尺寸比铜颗粒要大的多。断口分析结果显示,钨铜覆层的断口形貌不同于传统的断口形貌。钨铜结合面的形貌分析表明,钨铜合金密实的烧结在了铜基体的表面。     

节理岩体爆破的损伤机理及其块度模型

在分析现有岩体爆破机理与块度计算模型的基础上, 提出了考虑工程岩体的尺寸效应、将宏观结构弱面引入岩体爆破物理过程来建立块度模型的观点。为此, 按照损伤力学的处理方法, 应用连续介质损伤理论研究爆破过程中岩体弱面的破裂机制, 给出了岩体沿节理破裂的损伤发展方程。从爆破岩块具有分形特征的思想出发, 通过提出“岩体破裂比率”概念, 将爆破块度计算同节理岩体爆破机制相联系, 建立起岩体爆破块度的损伤力学模型（ＢＤＭ） , 该模型反映了岩体沿节理面破裂和岩石本身破裂的岩体爆破本质     

微喷砂时间对陶瓷刀具表面完整性影响研究北大核心

针对陶瓷刀具高速切削高温合金时刀具磨损严重的问题,采用微喷砂处理技术对Sialon基陶瓷刀具表面进行处理,研究喷砂时间对Sialon基陶瓷刀具表面完整性(微观形貌、表面粗糙度、维氏硬度、断裂韧度、残余压应力)的影响规律,提升陶瓷刀具表面完整性,从而提高刀具耐磨性。研究表明:在喷砂4 min、喷砂压强0.4 MPa的条件下,陶瓷表面微观缺陷得到改善,断裂韧度提升32%,残余压应力提升12%,可以获得综合水平较高的表面完整性,为陶瓷刀具微喷砂处理参数的选择提供理论性指导,有助于提升陶瓷刀具表面完整性。     

管式连铸结晶器爆炸成形与修复质量分析

对近年来利用爆炸成形技术成形与修复内腔精度高且形状复杂的管式连铸结晶器质量进行了总结,并在大量实验和数值模拟的基础上,对爆炸成形与修复过程进行了分析.分析结果表明,采用爆炸成形加工方法成形与修复管式结晶器可以达到良好的成形精度,且爆炸硬化效应明显,药量等诸多影响因素对成形结果至关重要.这对进一步提高应用爆炸成形与修复管...     

钛/铝复合板爆炸焊接技术研究进展

通过爆炸焊接技术制备的钛/铝复合板可兼具钛合金耐腐蚀性和铝合金低成本的优点。对钛/铝复合板爆炸焊接技术的研究进展进行介绍,论述了炸药种类、质量比R、基覆板间距及爆炸焊接窗口等主要工艺参数对钛/铝复合板组织和性能的影响;分析了影响钛/铝复合板结合界面的主要因素——金属间化合物种类、扩散层和界面波形;对钛/铝复合板硬度、抗剪切强度、抗拉强度及拉伸断口的研究进行了汇总分析。最后,指出了钛/铝复合板爆炸焊接工艺研究的重点发展方向。     

THEORETICAL AND EXPERIMENTAL STUDIES ON FRACTURE PLANE CONTROL BLAST WITH NOTCHED BOREHOLES

１ＩＮＴＲＯＤＵＣＴＩＯＮＤｕｒｉｎｇｒｅｃｅｎｔｙｅａｒｓ，ｑｕｉｔｅａｆｅｗｉｎｖｅｓｔｉｇａｔｏｒｓｈａｖｅｗｏｒｋｅｄｏｎｆｒａｃｔｕｒｅｐｌａｎｅｃｏｎｔｒｏｌｂｌａｓｔｗｉｔｈｎｏｔｃｈｅｄｂｏｒｅｈｏｌｅｓ．Ｓｕｃｃｅｓｆｕｌａｐｐｌ...     

Simulation and Improvement of the Micro Abrasive Blasting Process

Micro abrasive blasting (MAB) is becoming an important machining technique for the fabrication of Micro Electro Mechanical systems. The process is based on the erosion of a mask-protected brittle substrate by an abrasive-laden air jet. Currently available blasting machines are relatively simple. However, to exploit this technique for applications of industrial interest a more efficient and controllable process is required. In this paper abrasive blasting is analysed by means of a set of models containing different sub-models for the particle beam, the material removal mechanism and the resulting blasting profile. A new line-shaped Laval nozzle has been developed, which is able to increase the particle velocity by 40% compared to a conventional round nozzle. The blasting-profile of this line-shaped nozzle is more uniform and the material removal rate is significantly higher compared to conventional nozzles, which in turn leads to higher achievable aspect ratios of the three-dimensional microstructures.     

6066铝合金弹体破片形成机理

以挤压及热处理 (T6态 )工艺制备 6 0 6 6铝合金圆管型模拟炸弹 ,进行了力学性能测试、砂坑中爆破试验及扫描电镜断口形貌观察。研究结果表明 :随着应变速率的提高 ,6 0 6 6铝合金强度升高 ,塑性下降 ,断口从韧性向脆性转变。爆破破片断口形貌由拉伸断裂、剪切断裂及其过渡区组成 ,但以拉伸断裂为主。6 0 6 6铝合金作为弹体材料密度小、装药量大、爆轰力大 ,故而破片率及破片初速大 ,杀伤力大。通过破片的断裂特征 ,分析了与材料动态断裂行为相关的形貌特征 ,研究了该弹体材料的膨胀断裂行为     

水下爆炸焊接制备NiTi合金与铜箔复合板

应用水下爆炸焊方法进行了NiTi形状记忆合金与铜箔的爆炸焊研究．利用大型有限元软件ANASYS／LS-DYNA对水下爆炸冲击波驱动飞板的飞行过程进行了数值模拟．飞板的飞行速度与爆炸焊产生射流的最小碰撞速度对比表明,可以实现焊接．通过分析微观组织和断裂机理,评估复合板焊接效果．结果表明,微观组织观察显示界面为连续均匀的波纹形态,界面结合处无裂纹,焊接性能良好．断口形貌分析显示断裂主要表现为解理和准解理断裂,界面处端口形貌与微观组织形态观察一致．水下爆炸焊方法将解决脆性、薄板金属用传统爆炸焊方法难以焊接的问题．     

在用氧气瓶爆炸原因分析

根据事故现场、以及对气瓶碎片进行的宏观检验、化学成分分析、力学性能测试、宏观断口分析结果，确定该气瓶爆炸性质为化学爆炸。本文分析了爆炸事故的原因，并提出了相应的防范措施。     

爆破器材库选址与总图设计要点

根据多年从事总图设计工作的经验 ,指出在爆破器材库的库址选择及总图设计中 ,既要充分考虑地理位置与地形条件 ,又要考虑周围环境的相互影响和干扰 ,以及交通便捷、防火防洪安全等问题 ,以确保库区自身安全及对外安全 ,确保生产 ,节省投资