共查询到20条相似文献,搜索用时 163 毫秒
1.
改善TiAl基合金显微组织新工艺的研究 总被引:8,自引:0,他引:8
研究了复合热机械处理新工艺技术对(Ti-33Al-3Cr)-0.5Mo(wt%)合金显微组织的影响,试验结果表明,适当的复合热机械处理工艺能够使TiAl基合金铸态粗大的层片状晶团充分,完全破碎,获得各种形态的,均匀细小的显微组织,并分析了新工艺技术的热塑性变形及热处理对显微组织的影响。 相似文献
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本文综述了机械合金化Al-Al_3Ti材料的发展现状,论述了增强体Al_3Ti的性质和机械合金化制备的Al-Al_3Ti的组织与性能。采用机械合金化制备的Al-Al_3Ti具有理想的组织。相当高的强度与塑性,良好的热强性。目前对机械合金化制备的Al-Al_3Ti的研究不够深入,还需进行大量的工作。 相似文献
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以Ti,Al,C粉末为原料,用热爆反应法制备了原位TiC颗粒增强的TiC/Al的Al基复合材料。研究了Ti-Al-C系热爆合成过程,探讨了热爆合成TiC粒子的形成机制。研究表明:生成的TiC粒子呈球形,尺寸均匀,且随体系中含Al量的增加,热爆反应合成TiC的温度降低,TiC颗粒尺寸减小。 相似文献
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Ti—Al—C系热爆反应制备TiC/Al复合材料的研究 总被引:4,自引:0,他引:4
以Ti,Al,C粉末为原料,用热爆反应制备了原位TiC颗粒增强的TiC/Al的Al基复合材料。研究了Ti-Al-C系热爆合成过程,探讨了热爆合成TiC粒子的形成机制,研究表明,生成了TiC粒子呈球形,尺寸均匀,且随体系中含Al量的增加,热爆反应合成TiC的温度降低,TiC颗粒尺寸减小。 相似文献
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采用机械合金化方法制备Al-Ti合金时,球磨时间影响粉体的粒度、结构和相组成,从而影响合金成型后的组织结构与性能。经过足够长时间球磨后,Al、Ti混合粉转变为单一Al(Ti)过饱和固溶体,且颗粒细小均匀;成型后可获得Al基体上弥散分布细小Al3Ti颗粒的Al-Ti合金。 相似文献
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球磨时间对机械合金化Al—8Ti合金组织的影响 总被引:3,自引:1,他引:2
采用机械合金化方法制备Al-Ti合金时,球磨时间粉体的粒度、结构和相组成,从而影响合金成型后的组织结构与性能。经过足够长时间球磨后,Al、Ti混合粉转变为单一Al(Ti)过饱和固溶体,且颗粒细小均匀;成型后可获得Al基体上弥散分布细小Al3Ti颗粒的Al-Ti合金。 相似文献
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Ti-48Al-2Cr-2Nb合金的研究和应用早在60年代初,以TiAl为基的γ固溶体合金由于其优异的高温持久和蠕变性能受到了人们的关注。美国空军认为TiAl基合金对于喷气发动机热端部件的减重具有巨大的潜力。从铸造TiAl基合金和铸造高温合金性能的对... 相似文献
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《Materials Science & Technology》2013,29(12):1489-1498
AbstractA new processing technology, direct chill rheocasting (DCRC), has recently been developed by BCAST at Brunel University, for production of high quality Mg alloy billets and slabs. In the present paper the authors present the DCRC process and experimental results on microstructure and mechanical properties of DCRC billets. Basically, the DCRC process consists of a high quality semisolid slurry supply system, continuously feeding a conventional direct chill caster, to produce billets or slabs. Experimental results show that the DCRC billets have a fine and uniform microstructure throughout the cross section, the average grain size being ~50 μm. Direct extrusion of the DCRC billets was conducted to assess the deformability and mechanical properties after extrusion. The average grain size is <3 μm in the as extruded state. The increased deformability of the DCRC billets has been attributed to the fine and uniform microstructure, while the improved mechanical properties of the extruded product is attributed to the fine grain size. 相似文献
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A new semisolid metal processing technology, rheo-diecasting (RDC) has been developed for production of Mg-alloy components
with high integrity. The RDC process innovatively combines the dispersive mixing power of the twin-screw mechanism for creation
of high quality semisolid slurry and the high efficiency, low cost nature of the high pressure die casting (HPDC) process
for component shaping. AZ91D Mg-alloy was used to optimise the RDC process and to establish its advantages over both the HPDC
process and other existing semisolid processing techniques. In this paper we present the RDC process for processing Mg-alloys
and the resulting microstructure and mechanical properties of RDC AZ91D alloy. The solidification behaviour of the Mg-alloys
in the RDC process and the co-relationships between microstructure and mechanical properties of the RDC AZ91D alloy are discussed.
It was found that the RDC process is capable of producing Mg-alloy samples with close-to-zero porosity and a fine, uniform
microstructure throughout the entire sample irrespective of the section thickness. Compared with those obtained by other existing
processing techniques, the RDC samples have substantially improved or equivalent mechanical properties, with the tensile elongation
showing more than 100% improvement. 相似文献
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消失模铸造AZ91镁合金的研究 总被引:13,自引:1,他引:12
研究了ZA91镁合金消失模铸造时铸件的厚度,位置和真空度对铸件质量,组织及力学性能的影响,真空度是决定铸件质量的一个关键的工艺因素,无真空时浇注铸件易产生浇不足缺陷,但真空度过大又会导致形成粘砂和气孔等缺陷,真空浇注射明显细化组织,但真空度进一步增大时细化效果野 不明显,铸件显微组织具有很大的壁厚效应,然 位置对组织的影响与是否采用抽真空措施有关,铸件壁厚较小时,铸件的力学性能总体较差,断裂源自Mg/Mg17Al12界面、且主要是以解决理形式的脆性断裂。 相似文献
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目的 传统多道焊缝搭接模型存在沉积环境不对称、热量累积严重及最终成形质量差的问题,针对以上情况,提出了间隙填充模型,并研究了该模型对成形质量及组织性能的影响。方法 以4043铝合金为填充材料,探究了沉积顺序、沉积方向、道间冷却时间及CMT电弧模式对搭接质量的影响。确定了多层多道沉积策略,分别基于间隙填充模型和传统搭接模型进行了长方体式试样的沉积,对比分析了所成形试样的成形质量、微观组织及力学性能。结果 当送丝速度为5 m/min、焊接速度为0.6 m/min时,在CMT+P的电弧模式下,采用由内而外的沉积顺序、道间反向的沉积方向及无道间冷却时间的工艺组合所成形试样的搭接质量最佳,所沉积试样的表面不平度低于0.004mm2。结论 由间隙填充模型和传统搭接模型所成形试样的微观组织和力学性能并无明显差异,但基于间隙填充模型的沉积策略所成形的试样的成形质量更好。其顶部微观组织主要由柱状晶组成,底部微观组织以细小的等轴晶为主,中部的热影响区主要为粗大的柱状晶,且晶粒尺寸分布不均匀,而焊缝区主要由细小的等轴晶和柱状晶组成。 相似文献
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A new surface-treatment process using a thin layer of primary explosive was applied to a 316L type stainless steel. The induced microstructural modifications and the residual mechanical properties of the treated material have been evaluated. The surface roughness quality and the microhardness increase are higher than after usual shot-peening treatments. The near-surface microstructure, observed by transmission electron microscopy, is composed of numerous mechanical twins the density of which decreases with increasing depth. The yield strength (0.2% offset) of the treated layer has been evaluated and related to the mean value of the microhardness in this layer. 相似文献
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Dang Khoa Do 《Virtual and Physical Prototyping》2016,11(1):41-47
Selective laser melting is an advanced manufacturing process which can control the microstructure evolution and mechanical properties of as-manufactured products via various processing parameters. In this study, the porosity/relative density, surface quality, microstructure and mechanical properties were investigated on the selective laser melted Ti-6Al-4V alloy specimens fabricated with a wide range of laser energy inputs. It was found that the microstructure of selected laser melted Ti-6Al-4V alloys is typical of acicular martensites α′. Quantitative analysis reveals that the relative density, martensitic lath size and microhardness increase with the laser energy input. The surface quality is also substantially affected by the energy input. 相似文献
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The effect of Ca,Ba,Bi and Al on the amountof carbide in ductile iron weld metal,themicrostructural characteristics of ADI weld metaland the effect of heat treatment process on themicrostructure and mechanical properties of ADIweld metal have been studied.On this basis theoptimum composition of weld and the optimumheat treatment process of ADI weld metal were de-termined and a new electrode for arc cold-welding(i.e.,without preheat) of ADI was developed.Theductile iron welded joint free from eutectic carbidecan be produced by using this electrode beforeaustempering and the weld metal obtained afteraustempering has a microstructure and mechanicalproperties similar to those of ADI.The mechanicalproperties of welded joints can match the require-ment of ADI. 相似文献
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基于平面应变压缩模型的TA15钛合金热强旋组织性能预测研究 总被引:1,自引:0,他引:1
针对热强旋过程的变形特点,本文研究了基于平面应变压缩的物理模拟模型对钛合金热强旋过程的组织性能演变预测的可行性.为此本文对TA15钛合金平面应变压缩变形的组织和热强旋过程进行了对比分析,并以平面应变压缩的组织性能演变模型为基础,采用BP神经网络对TA15钛合金热强旋旋过程的组织性能进行了预测.研究结果表明,TA15钛合金平面压缩变形和热强旋过程的组织性能演变规律基本一致,采用平面应变压缩的组织性能模型可有效预测钛合金热强旋过程的组织演变.但是,由于强力旋压的多道次累积变形较平面压缩的单道次变形更为均匀充分,使得大减薄率时的预测误差略有增大趋势. 相似文献
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金属构件的塑性加工不仅需要控制其形状尺寸,还要调控其微观组织和力学性能,以获得满足服役要求的产品。构件成形结束后,常需要通过热处理工艺调控其组织和性能,但由于成形过程中的变形参数影响其热处理前的微观组织,因此,也影响到其热处理过程的组织演变,进而影响构件的服役性能,导致热处理调控更加复杂。本文基于机器学习的方法,考虑变形参数对热处理的影响,建立了Ti2AlNb合金构件高温成形过程微观组织和力学性能的预测模型,并与有限元模拟软件结合,建立了Ti2AlNb合金构件成形-热处理的全流程模拟方法。本文通过该方法对Ti2AlNb管材高温压制-时效处理工艺进行了全流程的模拟,模拟结果表明变形和热处理参数均会对成形构件的组织和力学性能产生影响。进而通过成形和热处理实验对模拟结果进行了验证,模拟结果与实验结果的一致性较好。说明通过该方法,可以实现构件成形-热处理全流程的模拟和组织-性能预测,可用于指导加工工艺的制定。 相似文献
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20CrMnTi钢齿轮渗碳质量的控制 总被引:1,自引:1,他引:0
要承勇 《理化检验(物理分册)》2001,37(12):527-530
采用理化测试手段,研究了渗碳工艺参数对20CrMnTi齿轮的微观组织、力学性能、显微硬度及残余应力的影响,分析了影响渗碳层质量的因素,提出了控制热处理工艺的方法。 相似文献