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LY2铝合金塑韧性能差,表面硬高也不高,使其应用受到限制。采用激光束对LY2铝合金表面进行激光冲击强化处理。采用显微硬度计、热模拟试验机和扫描电镜研究了LY铝合金激光冲击强化前后的显微硬度、拉伸力学性能和形貌。结果表明:经1次、3次激光冲击强化后,LY2铝合金的表面硬度分别提高了32%和43%,抗拉强度分别提高了15%和19%,屈服强度分别提高了18%和22%,断后伸长率均分别提高了23%和26%,强化冲击次数对LY2铝合金拉伸力学性能提高程度的影响不明显;激光冲击强化能够提高LY2铝合金的塑韧性。 相似文献
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激光冲击是一种利用等离子冲击波效应的表面强化技术,该技术能显著提高金属材料抗疲劳、磨损、腐蚀等性能。简要阐述了激光冲击强化技术原理、特点及激光诱导的等离子体特性。从激光冲击强化后金属的疲劳行为、强化机理及疲劳延寿机制3个方面总结了国内外激光冲击强化在金属零部件抗疲劳性能方面的研究进展。激光冲击强化机理由最初的残余压应力强化机制转变为目前普遍接受的残余压应力和表面纳米化复合强化机制。冲击后的金属零部件表层硬度显著提高,由表层向内部引入较大的残余压应力,表层晶粒碎化至纳米级,而表面粗糙度基本保持不变,尤其适合表面粗糙度要求较高的最终零部件的强化。在总结疲劳性能研究及强化机理的基础上,对目前激光冲击强化研究中存在的问题进行探讨,并指出下一步研究的关键问题。 相似文献
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高压水射流参数对材料表面强化性能的影响 总被引:1,自引:0,他引:1
高压水冲击强化是一种新的表面强化方法,通过改善零件的表面状态而提高疲劳寿命.本文通过淹没射流的方法,选用铝合金7075T651作为实验材料,研究了高压水射流工艺参数对冲击强化的影响规律,并测试了材料表面强化的效果.结果表明:试件经高压水冲击强化后,其拉伸疲劳极限比未强化和喷丸强化条件下分别提高了22%和6.6%.由于高压水强化比喷丸强化得到了更好的表面状态,强化后的表面轮廓连贯平滑、浅表层压应力高,因而能更大程度提高强化件的疲劳性能. 相似文献
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方形光斑激光冲击强化金属表面的耐腐蚀性能及机理 总被引:2,自引:0,他引:2
使用25J和30J脉冲能量的方形光斑激光冲击强化技术对20CrMnTi钢表面进行强化。测量强化后样品表面的分层设色形貌图、粗糙度、显微硬度和残余应力,研究样品的极化曲线和盐雾腐蚀后的表面形貌。结果表明:激光冲击强化使得表层材料发生塑性变形,试样表面粗糙度Ra降低到0.433μm,显微硬度得到提高,并产生较大的残余压应力。合适的激光功率密度使得材料的强化层和钝化膜的密度增加,产生的横向残余压应力使得钝化膜更加稳定,从而提高材料的耐腐蚀性能。过大的激光功率密度导致材料表面出现压痕、铝箔发生烧蚀等现象,使得Cl-在压痕缺陷处聚集,材料表面局部产生拉应力,表面钝化膜被破坏,加快表面的腐蚀速率。 相似文献
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李涛丁文文 《真空科学与技术学报》2020,(4):342-346
采用时效工艺处理发动机用FGH96镍基高温合金,利用激光冲击强化方法对其表面进行修复,实验测试分析其组织,残余应力及疲劳寿命。研究结果表明:基体中形成了大量的γ相奥氏体;时效96h后显微组织中产生了大量碳化物,存在沿晶析出。激光冲击强化处理后位于表面附近的晶粒形成更小的尺寸,合金表面晶粒发生明显细化,链状碳化物在晶粒内呈现弥散分布状态,实现FGH96合金的沉淀强化作用,对位错运动产生明显抑制效果。经激光冲击强化处理后试样并未产生新的衍射峰。激光冲击强化可以使试样表面获得更高的残余压应力,使时效试样达到更高的疲劳寿命。激光冲击强化还可以将残余应力引入到基体中,使疲劳裂纹源受到明显抑制,显著降低疲劳裂纹的扩展速度。 相似文献
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Guoxin Lu Jing Li Yongkang Zhang David W. Sokol 《Materials and Manufacturing Processes》2019,34(6):598-603
The stress effect generated by a high-energy short-pulse laser is utilized to achieve performance enhancement or precise shaping of metal material components in laser shock technology. A method of marking metal materials using laser shock technology is introduced in this paper. The physical principle is the effect of thickness of absorbing layers on the intensity of a laser-induced shockwave, which results in forming the mark with a certain shape using local surface plastic deformation. The marking method based on the principle of laser shock overcomes the deficiency of traditional marking methods that causes serious damage to the surface of the metal material and leads to a decrease in service performance. Laser shock marking(LSM) allows the surface of the metal material to form a predetermined mark, which also improves the service performance accordingly. 相似文献
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采用连续高功率固体Nd-YA G激光辐照, 使预置于NiTi 合金表面的Ti 粉在N2 环境中形成TiN 增强Ti 基复合材料涂层。选择适当的激光辐照工艺参数, 获得致密的TiN 增强金属基复合材料激光改性层。SEM 观察及EDAX 成分分析结果表明, TiN/ Ti 金属基复合材料表面改性层与基体NiTi 合金存在良好的冶金结合, 界面处成分均匀过渡, 表面Ni 含量极低。显微硬度测试及磨损实验表明, TiN/ Ti 金属基复合材料改性层显著提高了NiTi 合金的表面硬度和耐磨性, 激光表面改性层可有效地改善NiTi 合金作为生物医学材料使用的表面成分和性能。 相似文献
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Effect of laser peening on fatigue performance in 300M steel 总被引:1,自引:0,他引:1
T. E. PISTOCHINI M. R. HILL 《Fatigue & Fracture of Engineering Materials & Structures》2011,34(7):521-533
This study investigated and quantified the ability of laser peening to extend fatigue life and mitigate common fatigue crack nucleation mechanisms including foreign object damage and stress corrosion cracking in high strength, 300M steel. Residual stress was measured and fatigue tests were completed for as‐machined, shot peened and laser peened coupons tested under a variety of conditions including in a corrosive environment and with simulated foreign object damage. The results are compared to available reference data studying the application of another emerging surface treatment, low plasticity burnishing, to the same material (300M steel) and in similar coupons. Laser peening resulted in large stress‐life improvements in each condition, with a 54% increase in fatigue strength in an air environment for laser peened coupons at a lifetime of one million cycles. Additional fatigue testing in the 300M program showed that laser peening mitigated fatigue strength losses and improved the lifetimes (relative to as‐machined, air environment) for coupons subject to either a corrosive environment or simulated FOD. Performance of laser peened coupons under all conditions proved to be better than reference data for coupons treated with shot peening or low plasticity burnishing. 相似文献
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Guoxin Lu Huan Liu Chaohui Lin Pratik Shukla Yongkang Zhang 《Materials Science & Technology》2013,29(15):1781-1788
This paper summarises the regulation mechanism of the traditional and emerging surface strengthening treatments – mechanical shot peening (SP) and laser shock processing (LSP) treatment, respectively – on the fretting fatigue behaviour of the tenon joint materials of aero-engine cold-end parts, as surface strengthening treatment contributes to the improvement of service performance. From the point of view of the actual service environment of turbine components, this paper also expounds on the key problems faced by surface strengthening treatments in improving the mechanical properties of joint materials for aero-engine hot-end components. The application of LSP in the fretting fatigue life extension of turbine joint materials has strong feasibility and development prospects. 相似文献
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C. Brent Dane Lloyd A. Hackel James Daly James Harrisson 《Materials and Manufacturing Processes》2000,15(1):81-96
Laser shot peening, a surface treatment for metals, is known to induce compressive residual stresses of over 1 mm (0.040 inch) depth providing improved component resistance to various forms of failure. Additionally recent information suggests that thermal relaxation of the laser induced stress is significantly less than that experienced by other forms of surface stressing that involve significantly higher levels of cold work. We have developed a unique solid state laser technology employing Nd:glass slabs and phase conjugation that enables this process to move into high throughput production processing. 相似文献
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《纳米技术与精密工程》2019,(2)
Additive manufacturing(AM) of metals often results in parts with unfavorable mechanical properties. Laser peening(LP) is a high strain rate mechanical surface treatment that hammers a workpiece and induces favorable mechanical properties. Peening strain hardens a surface and imparts compressive residual stresses improving the mechanical properties of a material. This work investigates the role of LP on layer-by-layer processing of 3 D printed metals using finite element analysis. The objective is to understand temporal and spatial residual stress development after thermal and mechanical cancellation caused by cyclically coupling printing and peening. Results indicate layer peening frequency is a critical process parameter affecting residual stress redistribution and highly interdependent on the heat generated by the printing process. Optimum hybrid process conditions were found to exists that favorably enhance mechanical properties. With this study, hybrid-AM has ushered in the next evolutionary step in AM and has the potential to profoundly change the way high value metal goods are manufactured. 相似文献
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对16MnR母材进行激光冲击工艺实验,获得优化的激光冲击工艺参数。对激光-MAG复合焊焊接接头进行表面处理,分析接头激光冲击前后状态的残余应力分布及抗应力腐蚀性能变化。结果表明:对16MnR钢平板经激光冲击处理后,在材料表面最大可引入475μm厚度的塑性变形层,并同时引入-593 MPa的压应力分布。采用优化激光冲击工艺对16MnR钢焊接接头进行表面处理后,可有效减小焊接接头表面的残余拉应力分布。在3.5%NaCl(质量分数)条件下对激光冲击处理前后的接头试样进行慢应变速率应力腐蚀实验,发现激光冲击处理前后16MnR钢焊接接头的应力腐蚀敏感指数I_(SSRT)分别为0.106和0.104,表明激光冲击可以提高接头的抗应力腐蚀能力。 相似文献
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Susil K. Putatunda Leslie Bartosiewicz Robert J. Hull Michael Lander 《Materials and Manufacturing Processes》1997,12(1):137-151
Austempered ductile cast iron (ADI) has emerged as a major engineering material in recent years. In addition to high strength and relatively light weight (compared to steel), it has high ductility, good wear resistance and good damping capacity. It has many potential applications such as automotive components (e.g. crank shafts and gear boxes) as well as aircraft components (landing gears).
In many structural applications, (e.g. aircraft landing gear) it is often required that the material be hardened at the surface while the interior of the material must remain soft or ductile. The higher hardness at the surface layer imparts excellent wear resistance while the soft inner core provides higher toughness and fracture resistance. The conventional methods of surface hardening such as carburizing and nitriding or shot peening have several limitations, e.g. retained austenite, massive carbide formations and insufficient case depth. In recent years, there has been significant interest in use of laser in surface treating of materials. Surface hardening by means of laser is a very useful technique because of self quenching and minimum of distortion. Laser hardening can also improve significantly the surface properties such as wear and fatigue resistance. 相似文献
In many structural applications, (e.g. aircraft landing gear) it is often required that the material be hardened at the surface while the interior of the material must remain soft or ductile. The higher hardness at the surface layer imparts excellent wear resistance while the soft inner core provides higher toughness and fracture resistance. The conventional methods of surface hardening such as carburizing and nitriding or shot peening have several limitations, e.g. retained austenite, massive carbide formations and insufficient case depth. In recent years, there has been significant interest in use of laser in surface treating of materials. Surface hardening by means of laser is a very useful technique because of self quenching and minimum of distortion. Laser hardening can also improve significantly the surface properties such as wear and fatigue resistance. 相似文献