Correction: Novel Surface Topography and Microhardness Characterization of Laser Clad Layer on TC4 Titanium Alloy Using Laser-Induced Breakdown Spectroscopy and Machine Learning

Metallurgical and Materials Transactions A -     

TC4合金成分及组织的研究

通过对抚顺特钢20炉TC4合金成分及组织分析观察,精选原材料、合理工艺控制,可以满足钛材料成分一致性,组织均匀性,高的质量稳定性。     

固溶-时效对TC4钛合金显微组织和力学性能的影响

采用不同制度固溶-时效的热处理方式对TC4 钛合金棒材进行热处理,并通过金相观察、力学性能检测研究了固溶-时效对钛合金棒材的微观组织和力学性能的影响.金相观察发现,固溶后大部分α相转变为亚稳相β相、α'相和α"相,时效处理后将亚稳相转变为细小稳定等轴组织与片层组织.力学性能检测结果表明:固溶水淬延迟时间在10s,时效温...     

钛合金表面焊接碳化钨硬质合金层厚度的有限元模拟设计

在Ti6Al4V合金表面焊接上适当厚度的碳化钨硬质合金,是提高其表面强度和耐磨性的一种行之有效的方法.作为一种整体结构件,在实际应用中碳化钨硬质合金层的厚度对部件的内应力分布以及尺寸稳定性有着重要的影响.因此从实际工况出发,利用先进的纳米显微力学探针测量了材料的弹性模量,然后采用ANSYS有限元软件,对钛合金表面焊接碳化钨硬质合金层,在受压情况下的应力分布和整体变形情况进行分析,以此对碳化钨合金层的厚度进行模拟,结果表明,当碳化钨合金层厚度在0.25～0.5 mm时,最大等效应力发生在钛合金和碳化钨合金层之间,容易引起界面处裂纹的产生;合适的碳化钨硬质合金层厚度范围应在0.5～1.5 mm之间,最佳的厚度应该是1 mm左右.     

TC4-DT钛合金高周疲劳行为研究

对TC4-DT钛合金的高周疲劳性能及断口形貌进行了研究。结果表明：TC4-DT钛合金的S-Ⅳ曲线（应力比R=-1）不出现呈水平线的疲劳极限,10^7次不被破坏的条件疲劳极限为550MPa,置信度为95％;疲劳裂纹源均出现在试样的表面,疲劳裂纹扩展区较大说明材料具有较高的断裂韧度;疲劳裂纹扩展区由许多解理小刻面组成,解理面上可见疲劳条带及二次裂纹,以解理断裂为主;断裂区断口表面由许多互相连接的凹坑所组成,主要表现为韧窝断裂。     

TC4-DT钛合金热变形机制及加工图

用Gleeble-1500型热模拟机研究TC4-DT钛合金在850~1 100℃、应变速率0.001~10 s-1、变形量70%条件下的高温压缩热变形行为,分析了该合金的流变应力行为以及显微组织演变规律,建立了该合金的本构关系模型以及热加工图。研究结果表明,TC4-DT钛合金在两相区和β相区的热变形激活能分别为544.03 k J·mol-1和264.32 k J·mol-1,分别大于纯α相和纯β相的自扩散激活能,表明TC4-DT钛合金热变形由高温扩散以外的过程控制。在两相区热变形时,原始组织发生了不同程度的球化,且变形温度越低球化效果越好。在β相区热变形时,低应变速率下(0.001~0.1 s-1)主要发生动态再结晶,而高应变速率(1~10 s-1)下主要发生动态回复,动态再结晶行为受到抑制。TC4-DT钛合金的失稳区主要分布在低温高应变速率区域,变形温度主要在850~940℃,应变速率主要在0.1~10 s-1,功率耗散率η值小于28%。     

钛合金TC4高温氧化特性研究

研究了最常用钛合金TC4在850~1 050℃的高温氧化特性,采用光学、扫描电镜观察、分析氧化层及富氧层形貌。结果表明,在研究的温度与加热时间范围内,TC4单位表面积氧化增重基本呈线性增长的规律;α单相区850℃温度加热的氧化皮形貌与950、1 000、1 050℃下明显不同。氧化过程中出现的内氧化层平均厚度仅和特定加热温度的氧扩散速率相关,与加热时间无关。此外,在富氧层内发现V的强烈富集。     

TC4钛合金的表面氧化及其对疲劳性能的影响

将TC4钛合金在300~850℃下进行了热处理,研究了不同温度处理后材料表面氧化层的特征变化和表面氧化层对材料疲劳性能的影响。结果表明,随温度的升高,氧化层的颜色发生了变化,氧化层的厚度增加,550℃后增加速度明显加快;试样在空气中经过800℃×3 h热暴露后,疲劳强度降低了约200 MPa。     

电流密度对TC4钛合金表面熔盐电解渗硼的影响

以TC4钛合金为基体进行熔盐电解渗硼,利用辉光放电光谱仪(GDOES)、扫描电镜(SEM)、X射线衍射仪(XRD)和显微硬度计研究电流密度对渗硼层厚度、成分、组织、相结构及硬度的影响。结果表明:电流密度在50~90 m A/cm2时,渗硼层晶粒随电流密度的增加由粗大变得细小,渗硼层厚度先增大后减小,电流密度为60 m A/cm2时渗硼层厚度最大。渗硼层不含Al,而V则易固溶于硼化物中。渗硼层主要由Ti B和Ti B2组成,在(111)晶面择优生长。渗硼层的显微硬度相对基体硬度提高了5倍。     

Effect of High-Power Ion Beams on the Surface Topography and Structure of the Subsurface Layer of Submicrocrystalline Titanium Alloys

Russian Journal of Non-Ferrous Metals - The influence of high-power beams of carbon ions (the ion energy is 250 keV; the pulse duration is ~100 ns; the current density in the pulse is 150–200...     

TC11钛合金疲劳性能及其断口特征

研究了ＴＣ１１钛合金三种不同显微组织的旋转弯曲疲劳性能及其断口特征，探讨微观机理，从理论上解决了三种显微组织即等轴、混合及片状组织的旋转弯曲疲劳性能差异之所在，为ＴＣ１１找到了旋转弯曲疲劳性能较好的显微组织提供了依据。     

Dynamics of Gradient Bioceramic Composite Coating on Surface of Titanium Alloy by Wide-Band Laser Cladding

Hydroxyapatite (HA) ,akindofbioactivematerial,haswideapplicationprospectinhardtissuereplacementandrepairbecauseofsimilarchemicalcompositionandcrystallographicstructuretothoseofbonemineral[1,2 ] .TheHAcoatingwithbioactivityandbiocompatibilityonthesur faceo…     

In Situ Laser Coating of Calcium Phosphate on TC4 Surface for Enhancing Bioactivity

 Titanium alloy has been a successful implant material owing to its excellent ratio of strength to weight, toughness, and bio inert oxide surface. Significant progress has been made in improving the bioactivity of titanium alloy by coating its oxide surface with calcium phosphates. In the present study, in situ coating was reported on Ti6Al4V(TC4) surface with calcium phosphate (Ca P) bioceramics synthesized and synchronously cladded by laser beam. This coating was grown by first preplacing directly the raw powders, which contain 80% of CaHPO4·2H2O, 20% of CaCO3, and dram of rare earth (RE), on the TC4 surfaces, and then exposing the surfaces to the laser beam with a power density of 1273-1527 MW·m-2 and a scanning velocity of 105 m/s. The resultant coating was characterized using scanning electron microscopy (SEM), X ray diffraction (XRD), thermogravimetric analysis and Different thermal Scanning (TG DSC), and Energy Dispersive X ray Detection (EDX). The results show that these laser ceramics include hydroxyapatite (HA), tricalcium phosphate (TCP), Ca2P2O7, and other Ca P phases, and the interface between the coating and the TC4 substrate has tighter fixation, in which the chemical bonding is approved. These laser hybrid coatings are useful in enhancing the bioactivity of titanium alloy surfaces.     

Investigation of Laser Surface Remelting Supported by Acoustic Emission Analysis and Machine Learning

Metallurgical and Materials Transactions A - In the present work, laser surface remelting (LSR) was carried out on C45 carbon steel using an Nd:YAG pulse laser. The effect of process parameters,...     

Effect of Yttrium on Microstructure and Hot Corrosion Preformance of Laser Clad Co-Based Alloy

The structure of the yttrium modified Co-base alloy layers formed by laser cladding on 2Cr13 and1Cr18Ni9Ti steel surfaces and its hot corrosion performance have been investigated systematically.The re-sults show that the Y-containing cobalt base clad alloy has a finer microstructure and higher corrosion re-sistance to the salt mixture of 75% Na_2SO_4+25%NaCl at high temperature.The unique properties are ob-tained with addition of 0.875% Y for the formation of a continuous and compact oxide scale.The compactscale may act as a barrier for the inward diffusion of oxygen and sulphur and also for the outward diffusionof alloying elements.     

影响TC4合金大规格锻棒表面质量和力学性能因素分析及工艺改进

针对TC4合金大规格锻棒生产表面出现大量裂纹,且力学性能不能达到国标要求的问题,分析了影响锻棒表面质量和力学性能的主要因素,提出了通过制定合理的加热工艺并尽量采用电加热炉加热、控制合金的终锻温度≥780℃及控制合金初锻单边压下量≤25 mm来提高棒材的表面质量;通过控制合金的配料为Al 6.4％左右、V4.2％左右、00.1％左右,方坯加热温度在相变点以下10℃至相变点以上5℃,方坯到棒材的变形量在30％以上来改善锻棒的力学性能.采取这些措施后,生产出的大规格TC4合金锻棒表面质量得到了较大改善,且力学性能可达到国标要求.     

钛及钛合金表面脆性α层的重腐蚀法测定

针对常规金相法测定钛及钛合金表面脆性α层的不足之处，根据脆性α层与钛基体在化学性质上的差异，采用重腐蚀法对不同热处理状态下钛及钛合金表面脆性α层的准确测定，弥补了常规金相法在测定方面的某些缺点，探讨了重腐蚀法测定脆性α层的原理和方法。     

Characterizing the Effect of Laser Power on Laser Metal Deposited Titanium Alloy and Boron Carbide

Titanium alloy has gained acceptance in the aerospace, marine, chemical, and other related industries due to its excellent combination of mechanical and corrosion properties. In order to augment its properties, a hard ceramic, boron carbide has been laser cladded with it at varying laser powers between 0.8 and 2.4 kW. This paper presents the effect of laser power on the laser deposited Ti6Al4V-B₄C composites through the evolving microstructures and microhardness. The microstructures of the composites exhibit the formation of α-Ti phase and β-Ti phase and were elongated towards the heat affected zone. These phases were terminated at the fusion zone and globular microstructures were found growing epitaxially just immediately after the fusion zone. Good bondings were formed in all the deposited composites. Sample A1 deposited at a laser power of 0.8 kW and scanning speed of 1 m/min exhibits the highest hardness of HV 432 ± 27, while sample A4 deposited at a laser power of 2.0 kW and scanning speed of 1 m/min displays the lowest hardness of HV 360 ± 18. From the hardness results obtained, ceramic B₄C has improved the mechanical properties of the primary alloy.