钨合金高弹速侵彻低碳钢板失效行为试验研究

研究钨合金破片对低碳钢板高速侵彻过程中的失效行为及诱发机制。通过弹道枪试验获得93W、95W两种球形钨合金破片以大于1500m/s的速度对Q235A钢板侵彻后的物理形态,对侵彻后受损破片进行了扫描电镜（SEM）观察与分析,结果表明：对于Q235A钢板,钨合金破片以大于1500m/s的速度侵彻后,93W是钨颗粒韧窝型穿晶断裂,95W是钨颗粒准解理型穿晶断裂;93W、95W合金破片局部均会发生熔化,50μm钨颗粒熔化冷凝后生成10μm以下的微米、亚微米尺度球形颗粒紧密排列,宏观上表现为破裂碎块的整体侵彻。     

钨合金高速侵彻低碳钢板失效行为实验研究

研究了钨合金破片对低碳钢板高速侵彻过程中的失效行为及诱发机制。通过弹道枪实验获得93W、95W 2种球形钨合金破片以大于1500 m/s的速度对Q235A钢板侵彻后的物理形态,对侵彻后受损破片进行了扫描电镜(SEM)观察与分析。结果表明:对于Q235A钢板,钨合金破片以大于1500 m/s的速度侵彻后,93W钨颗粒是韧窝型穿晶断裂,而95W钨颗粒是准解理型穿晶断裂;93W、95W合金破片局部均会发生熔化,50μm钨颗粒熔化冷凝后生成10μm以下的微米、亚微米尺度球形颗粒紧密排列,宏观上表现为破裂碎块的整体侵彻。     

93W与98W粉末冶金材料摩擦焊接头性能及组织分析

为了充分利用93W钨合金和98W钨合金两种粉末冶金材料各自独特性能优势,开发基于这两种钨合金的复合材质是非常必要的.采用自主研制的HSMZ-10型摩擦焊机,利用优选的焊接工艺参数,将93W钨合金和98W钨合金在主轴转速为2 000r/min,摩擦变形量为5 mm,摩擦压力为30 MPa,顶锻压力为60 MPa,摩擦顶锻变形速率为20 mm/s的条件下,通过摩擦焊接方法成功地实现了焊接,并对接头和母材进行了金相组织分析和力学性能检测分析.结果表明,接头力学性能良好,无未焊透等焊接缺陷;93W和98W粉末冶金材料之间无成分均一化现象,焊缝的强度大于母材.     

静液挤压93W合金变形与断裂研究

对静液挤压93W合金的微观组织、力学性能、变形与断裂特征进行了分析研究。结果表明：钨合金的强度随挤压变形量的增大而增加，其增加的幅度随挤压变形量的增大而减小，而延伸率则随挤压变形量的增大而减小；变形起始于粘结相，合金的变形属于典型的双相协调变形；裂纹萌生于钨．钨界面之间；静液挤压态钨合金的拉伸断口上钨颗粒解理断裂的比例明显高于未变形态。     

90W-7Ni-3Fe合金拉伸力学行为的应变率效应

采用CMT4105拉伸试验机对烧结态90W-7Ni-3Fe(90W)合金进行准静态拉伸试验;在较高应变率条件(1600~2000s-1)下,采用套筒加载直拉式Hopkinson拉杆对90W合金进行动态拉伸试验,研究90W合金在不同加载应变率下的拉伸性能及破坏机制。结果表明,在拉伸加载条件下,90W合金具有明显的应变率效应,随着应变率的增加,强度显著提高,材料断裂时的真实应变下降,断裂前吸收的总能量下降。90W合金的破坏机制由钨-钨界面开裂向钨颗粒解理断裂转变。     

大长径比钨丝/锆基非晶材料穿甲实验研究

针对80% Vf钨丝/Zr38Ti17Cu10.5Co12Be22.5非晶复合材料弹芯,在1300m/s~1700m/s撞击速度区间开展了侵彻30CrMnMo钢板实验研究,并与普通钨合金进行了对比。研究发现由这种材料制成的弹芯在高速侵彻时形成完全不同于钨合金和铀合金的侵彻特性,主要表现在：(1)在高速撞击条件下,钨丝/锆基非晶复合材料弹芯先后发生非晶气化、弹芯外侧钨丝屈曲和弯曲断裂、钨丝回流现象,使弹芯在侵彻过程中保持自锐,并且其侵彻能力高于普通93钨合金;(2)从弹、靶的破坏分析可知,这种复合材料在高速侵彻过程中形成自锐的同时,由于非晶气化,一方面会造成钨丝的动态屈曲与劈裂、弹芯刚度降低、侵彻分叉,会使侵彻过程中靶板抗力不对称,产生弹道弯曲等现象,相对减弱自锐性效果;另一方面,非晶气化导致回流的钨丝在弹坑侧壁产生沟槽划痕,气化形成的高压气体作用在弹坑划痕沟槽处易形成贯穿性裂纹,利于二次杀伤。     

钨丝/锆基非晶复合材料长杆体弹芯穿甲实验研究

针对体积分数为80%的钨丝/Zr_(38)Ti_(17)Cu_(10.5)Co_(12)Be_(22.5)非晶复合材料长杆体弹芯,开展了在1300~1700 m/s撞击速度下侵彻30CrMnMo钢板的实验研究,并与普通钨合金弹芯进行了对比。研究发现,由这种材料制成的弹芯在高速侵彻时形成完全不同于钨合金和贫铀合金的侵彻特性,主要表现在:(1)在高速撞击条件下,钨丝/锆基非晶复合材料弹芯先后发生非晶气化、弹芯外侧钨丝屈曲和弯曲断裂、钨丝回流现象,使弹芯在侵彻过程中保持自锐,并且其侵彻能力高于普通93钨合金;(2)这种复合材料在高速侵彻过程中,由于非晶气化,一方面会造成钨丝的动态屈曲与劈裂、弹芯刚度降低、侵彻分叉,会使侵彻过程中靶板抗力不对称,产生弹道弯曲等现象,相对减弱自锐性效果;另一方面,非晶气化导致回流的钨丝在弹坑侧壁产生沟槽划痕,气化形成的高压气体作用在弹坑划痕沟槽处易形成贯穿性裂纹,利于二次杀伤。     

SPS循环热处理对93W-4.9Ni-2.1Fe与95W-2.8Ni-1.2Fe-1Al_2O_3合金组织及性能的影响

利用放电等离子烧结(SPS)技术对具有相同理论密度的烧结态93W-4.9Ni-2.1Fe和95W-2.8Ni-1.2Fe-1Al_2O_3高密度钨合金进行循环热处理,并通过光学显微镜、SEM、TEM、EDS和三点弯曲实验分析循环热处理对两种合金显微组织和力学性能的影响规律。结果表明:随着SPS循环热处理次数的增加,93W-4.9Ni-2.1Fe合金在平均W晶粒尺寸未发生明显变化的同时,其粘结相中的W含量和位错密度不断升高,合金得到了固溶强化与位错强化,合金的硬度、抗弯强度、断裂挠度等性能相应提高;而对于95W-2.8Ni-1.2Fe-1Al_2O_3合金,由于更高的W含量和Al_2O_3颗粒的加入,烧结态时具有小得多的平均W晶粒尺寸、更大的W-W连接度和高硬脆特性,且SPS循环热处理对其组织和成分分布的均匀性影响程度相对较小,其力学性能虽然随SPS循环热处理次数的增加也得到了一定程度改善,抗弯强度和断裂挠度明显较93W-4.9Ni-2.1Fe合金的低,硬度则明显高于93W-4.9Ni-2.1Fe合金硬度。但循环热处理次数过多,反而会降低两种钨合金的硬度和断裂挠度。     

Y2O3对93WNiFe合金自锐性的影响

为了提高传统93WNiFe合金在侵彻装甲时的自锐化能力，采用粉末冶金的方法，在传统93WNiFe合金中加入了少量的Y2O3，经过1200℃氢气氛中预烧和1480℃烧结以及1100℃的真空退火热处理后烧结成为93W-Y2O3合金，其密度达到了理论密度的98．74％。静态力学性能测试结果表明：室温下抗拉强度为891MPa，延伸率为20％，保证了其作为穿甲弹战斗部用钨合金材料的基本力学性能；动态力学性能测试结果表明：在应变为0．28，应变率为3500s^-1时，93W-Y2O3合金内部出现了明显的裂纹及大量的微裂纹，而裂纹源正是起始于粘结相中的Y2O3陶瓷相。因此，在93W合金粘结相中形成的弥散Y2O3陶瓷相，可以作为钨合金中微裂纹的萌生源来诱发钨合金的剪切失效，进而可以提高对绝热剪切不敏感的93WNiFe合金材料的自锐化能力。     

钨合金性能对侵彻影响的数值模拟

采用LS-DYNA有限元软件建立钨合金高速侵彻Q235钢板过程的有限元分析模型(FEM),获得钨合金弹头侵彻过程速度变化及钨合金弹头变形、损伤和破坏演变规律,系统研究钨合金性能对侵彻过程的影响,表明钨合金密度、屈服强度和失效应变对弹头侵彻速度和破坏方式有显著影响,而钨合金硬化参量和应变率敏感系数的影响相对较小。研究结果有助于加深钨合金侵彻过程的认识,同时为制备侵彻性能优异的钨合金也提供了理论依据。     

93W/Ni/QSn4-3扩散焊接接头的显微结构和力学性能

采用扩散焊接的方法制备出加入Ni箔中间层的钨合金(93w)与锡青铜合金(QSn4-3)焊接接头样品.利用XRD,SEM和EPMA对焊接接头的物相组成和显微结构进行了分析,并测量了焊接接头样品的抗拉强度.结果表明,加镍的93W与QSn4-3进行扩散焊接时,焊接层的显微结构结合紧密,Ni与Cu元素之间以及93W合金的添加剂元素在Ni箔中分布存在明显的连续变化层.物相分析和显微硬度结果表明Ni元素与QSn4-3中的Cu元素和93W的添加剂元素的固溶反应,促进了93W,Ni/QSn4-3焊接接头强度的大幅度提高.

Abstract：

The 93W/Ni/QSn4-3 joint was prepared by diffusion bonding at vacuum using pure nickel foil as interface layer. The microstructure and composition were characterized by SEM and EP-MA. The tensile strength of joint was also measured. The test results show that Ni foil improves the tensile strength of 93W/Ni/QSn4-3 joint. The thickness of Ni interlayer becomes thiner obviously because of the diffusion layer between Ni element of Ni foil and W and additional elements of 93W alloy, as well as the gradient layer of Ni and Cu elements. Solution reactions between Ni element of Ni foil and Cu element of QSn4-3 alloy, W and additional elements of 93W alloy achieve the joint of 93W/Ni/QSn4-3, that is why tensile strength of 93W/Ni/QSn4-3 joint welded is improved.     

93W和97W钨合金破坏机制研究

对粉末冶金法制备的两种不同钨含量的钨合金材料进行SHPB试验和原位拉伸试验,研究了钨合金中钨含量与其显微组织、断裂方式及力学性能之间的关系。结果表明,在拉伸情况下随着钨含量的增加,钨合金的破坏方式由W-W间开裂转变为钨颗粒开裂,材料由韧性变为脆性。利用Ostwald烧结理论,对两种材料的微观结构进行预测,结果与实验符合较好。利用细观力学模型对所观察的实验结果进行了定量解释。烧结理论和细观力学相结合,可建立材料烧结条件、体积分数及力学性能之间的关系,为材料的设计、制备和力学性能的预测提供理论依据     

Densification behavior of nanocrystalline W–Ni–Fe composite powders prepared by sol-spray drying and hydrogen reduction process

This paper studied the densification behavior of nanocrystalline composite powders of 93W–4.9Ni–2.1Fe (wt.%) and 93W–4.9Ni–2.1Fe–0.03Y synthesized by sol-spray drying and hydrogen reduction process. The X-ray diffraction (XRD) analysis showed that γ-(Ni, Fe) phase was formed in the final obtained powders. Powders morphology characterized by scanning electron microscope (SEM) showed that the 93W–4.9Ni–2.1Fe nanocrystalline composite powders exhibited larger agglomeration and grain size compared with the 93W–4.9Ni–2.1Fe–0.03Y nanocrystalline composite powders. Both kinds of green compacts can obtain full density if sintered at 1410 °C for 1 h. When sintering temperature was above 1410 °C, the sintering density for both compacts decreased rapidly. In addition, the sintering density, densification rate and grain coarsening rate of 93W–4.9Ni–2.1Fe compacts were higher than those of 93W–4.9Ni–2.1Fe–0.03Y. The effect of trace yttrium on the densification behavior of nanocrystalline composite powders was also discussed.     

Effect of tungsten content on microstructure and quasi-static tensile fracture characteristics of rapidly hot-extruded W-Ni-Fe alloys

Tungsten heavy alloys (WHAs) with three different compositions (90W-7Ni-3Fe, 93W-4.9Ni-2.1Fe and 95W-3.5Ni-1.5Fe, wt.%) were heavily deformed by one-pass rapid hot extrusion at 1100 °C with an extrusion speed of ~ 100 mm/s and an extrusion ratio of ~ 3.33:1. The influence of tungsten content on the microstructure and tensile fracture characteristics of the as-extruded alloys was investigated in detail. The results show that the tungsten particles in the as-extruded 95W have the largest shape factor compared to the as-extruded 90W and 93W alloys and this implies that the tungsten particles in the as-extruded 95W alloy were subjected to the heaviest plastic deformation. In addition, ultimate tensile strength (UTS) and hardness (HRC) are significantly improved after rapid hot extrusion. The as-extruded 95W alloy processes the highest strength (1455 MPa) and hardness (HRC40) but the lowest elongation (5%), followed by the as-extruded 93W (UTS1390MPa; HRC39; 7%) and 90W alloys (UTS1260MPa; HRC36; 10%). The fracture morphology shows the distinct fracture features between the as-sintered alloys and the as-extruded alloys. For the as-sintered alloys, the fracture modes are various while transgranular cleavage of tungsten particles is the main characteristic in the as-extruded alloy. Meanwhile, the fracture modes of the three as-extruded alloys vary slightly with the tungsten content. TEM bright field images indicate that many lath-like subgrains with the width of 150-500 nm are present in the three as-extruded alloys, particularly in the as-extruded 93W and 95W alloys. Furthermore, the dislocations are absent in the γ-(Ni, Fe) phase. This means that dynamic recovery-recrystallization process took place during rapid hot extrusion.     

Effect of swaging on microstructure and tensile properties of W–Ni–Fe alloys

The objective of this study was to investigate the effect of swaging on the microstructure and tensile properties of high density two phase alloys 90W–7Ni–3Fe and 93W–4.9Ni–2.1Fe. Samples were liquid phase sintered under hydrogen and argon at 1480 °C for 30 min and then 15% cold rotary swaged. Measurement of microstructural parameters in the sintered and swaged samples showed that swaging slightly increased tungsten grain size in the longitudinal direction and slightly decreased tungsten grain size in the transverse direction. Swaging increased the contiguity values in both longitudinal and transverse directions. Swaging led to more severe deformations at the edges than at the center of the specimens. Solidus and liquidus temperatures of the nickel-based binder phase in the sintered and swaged samples were determined by differential scanning calorimetry measurements. An increase in tensile strength with a reduction in ductility was observed due to strain hardening by swaging.     

W450QN钢大气腐蚀性能

对武钢生产的W450QN钢进行了3年的大气暴露试验,结果表明,W450QN钢的耐蚀性优于Q345钢,在青岛站、江津站、琼海站,W450QN钢与Q345钢相比,平均腐蚀速率之比分别为1:1.48,1:1.45,1:1.44.带锈样的极化曲线测试结果显示,W450QN钢的致钝电流密度、维钝电流密度均比Q345钢小,说明其锈...     

Fabrication of W–Ni–Fe alloys with gradient structures

A sintering couple of green compacts with compositions of 88W–5Mo–4.9–2.1Fe and 93W–4.9Ni–2.1Fe respectively, were processed by liquid phase sintering. The microstructure and content of binding phase at different regions along the direction perpendicular to the original interface were investigated by scanning electron microscopy (SEM). The distribution of Mo content in composite was determined by energy dispersive analysis (EDS) and the micro hardness in different regions were measured by Vickers micro hardness tester. Results show that the grain size, volume fraction of binding phase and micro hardness vary gradually due to the graded distribution of molybdenum, which also introduces a solid/liquid interfacial tension gradient and the unbalanced liquid phase pressure serving as the driving force for liquid phase migration during liquid phase sintering.     

热轧W80Cu20合金的织构演变分析

采用XRD织构测试仪在角度为0°~90°时测量W80Cu20合金及经多道次热轧后的不完整极图,应用三维取向分布函数(ODF)研究W-Cu合金热轧板材中织构的演变规律。结果表明:热轧前,W80Cu20合金的取向密度值接近1,织构强度很弱,取向不明显,认为没有织构出现;W80Cu20合金轧制变形后,织构强度增加,表现出明显的轧制织构特征,择优取向明显,织构的取向密度值较大,形成稳定的织构组分:Brass型织构取向{110}<112>、Copper型织构取向{211}<111>和旋转立方织构取向{200}<011>。