氯化镁硬化剂硬化特性及工艺的优化

对氯化镁硬化剂的硬化特性及硬化工艺的优化问题进行了研究。生产表明，采用合理的硬化和氯化镁代替氯化铵、氯化铝硬化水玻璃型壳，常温强度高，高温强度和氯化铵硬化的型壳相当，但残留强度低，易清理，价格便宜。     

Thermoelastoplastic and Residual Stress Analysis during Induction Hardening of Steel

A theoretical model was developed to predict the thermoelastoplastic and residual stresses developed in a round steel bar during induction hardening. For numerical analysis, a quasi- static, uncoupled thermoelastoplastic solution based on the hyperbolic sine law of Tien and Richmond was formulated. The properties of the material were assumed to be temperature dependent. The phase transformation was considered in the numerical calculation, and the results were compared with the case where phase transformation is avoided. The cylinder was heated rapidly; once the temperature of the outer surface exceeded the transformation temperature, the cylinder was rapidly cooled. Accordingly, in the numerical calculation, only the area at the vicinity of the outer surface was assumed to transform to martensite. The results showed that the compressive residual stresses at the vicinity of the outer surface were considerably higher than the tensile stresses at the center.     

CA141载重车发动机缸体灰铸铁激光处理工艺参数优化及组织分析

用CO2激光器对用于CA141发动机缸体的灰铸铁材料表面进行激光处理,研究了激光功率和扫描速度等工艺参数对硬化层硬度和表面粗糙度的影响,从而优化了工艺参数,并对激光处理区的显微组织进行了观察分析.     

转向齿条接触式感应淬火技术

根据试验及生产实践经验，简述了汽车转向齿条接触式感应淬火的操作方法。     

淬火温度对Cr-Mo-V系低合金高强度钢力学性能的影响

研究了改变淬火温度对Cr-Mo-V系高强度力学性能的影响。结果表明，随着淬火温度的升高，硬度和强度逐渐提高，但当淬火温度超过1000℃后，硬度和强度的变化不明显。在所研究的整个淬火温度范围内，随着淬火温度的升高，塑性和韧性逐渐降低，且韧性的降低幅更大。由于添加了微合金元素V和Nb，当淬火温度低于1000℃，试验钢具有细小的奥氏体晶粒，逐渐降低，且韧性的降低幅度更大。由于添加了微合金元素V和Nb，当淬火温度低于1000℃，试验钢具有细小的奥氏体晶粒。     

钛合金表面电火花沉积强化研究现状

介绍了电火花表面沉积工艺的基本原理和技术特点，以及国内外电火花沉积技术在钛合金表面强化领域的研究现状。在钛合金表面进行电火花沉积，可得到具有高硬、耐磨、耐高温氧化、低摩擦系数的特殊表面涂层。虽然电火花表面强化技术具有特殊的强化效果，但存在着电火花强化层的表面粗糙度不容易控制、生产效率低、强化工艺不稳定的缺点。因此，今后要深入研究电火花放电机理，进一步提高强化效率，研究不同电极、基体材料的强化工艺。     

Total-FETI domain decomposition method for solution of elasto-plastic problems

In this paper we present an algorithm for the parallel solution of the rate-independent elasto-plastic problems with kinematic hardening. We assume the von Mises plastic criterion and the associated plastic flow rule. The time discretization is based on the implicit Euler method. The corresponding one-time-step problem is formulated in the incremental form with respect to the unknown displacement and discretized spatially by the finite element method. We use an ‘external’ algorithm based on a linearization of the elasto-plastic stress–strain relation by the corresponding tangential operator and we parallelize the arising linearized problem by the Total-FETI method. The numerical experiments were carried out using our novel C/C++ library FLLOP (FETI Light Layer On top of PETSc) at HECToR supercomputer located at EPCC, UK.     

在裂纹尖端引入奇异单元的偶应力有限元法

针对在微观状态下结构力学行为会受尺度效应影响的问题,在偶应力理论中考虑微观结构的旋转梯度可以较好解释结构的尺度效应.建立基于一般偶应力理论的有限元法的基本方程,并在裂纹尖端引入奇异单元,计算受单向拉伸的中心斜裂纹板裂纹尖端场的应力强度因子(Stress Intensity Factor,SIF),分析特征长度变化对SIF的影响,对比偶应力理论下的结果与经典理论下的结果.结果表明：在裂纹尖端引入奇异单元可以提高计算精度和稳定性;偶应力使得裂纹尖端SIF比经典理论下的值小,并且SIF随着特征长度增大而减小.     

一种基于虚拟机的驱动程序加固技术

近年来设备驱动程序可靠性技术已成为操作系统领域的研究热点。本文首先分析了驱动程序可靠性研究现状,介绍了虚拟机监控器技术;然后结合虚拟机技术,提出了一个新的驱动加固框架VHarden,重点研究了驱动域之间的数据传输和隔离保护机制,并基于开源的Xen虚拟机监控器和Linux操作系统,设计和实现了该原型系统;最后采用基于软件的故障注入工具对该原型系统进行了评测。测试结果表明,VHarden驱动加固结构可有效提高Linux操作系统的可用性。     

Characterization of laser hardened steels by laser induced ultrasonic surface waves

Ultrasonic surface waves are suitable for the characterization of surface hardened materials. This is shown on laser hardened turbine blades. The martensitic microstructure within the surface layer of surface hardened steels has a lower surface wave propagation velocity than the annealed or normalized substrate material. Because the propagation velocity depends on the ratio of layer thickness to wavelengthd/, its measurement allows the determination of the hardening depth. If the surface wave frequency is high enough, the surface wave propagates mainly within the hardened layer. A correlation of the surface wave velocity to the surface hardness has been found. Because the variation of the surface velocity in hardened steels is small, a high measurement accuracy is necessary to obtain the interesting hardening parameters with sufficient certainty. Therefore, a measuring arrangement has been developed where laser pulses, guided by optical fibers to the surface hardened structure, generate simultaneously surface wave pulses at two different positions. The two ultrasonic pulses are received by a piezoelectric transducer. The surface wave velocity is obtained from the time delay between these pulses which is determined by the cross-correlation method. To evaluate simultaneously surface waves with different penetration depths from the same signal acquisition, digital filtering has been used in connection with the cross-correlation.