7075铝合金棒材探伤不合格的原因分析及预防措施

通过显微组织、扫描电镜观察及能谱分析等手段,分析了7075铝合金棒材探伤不合格的产生原因,结果表明:铸锭中存在粗大金属化合物聚集,挤压变形时由于粗大的金属间化合物破碎产生微裂纹破坏了金属的连续性,导致探伤不合格。能谱分析结果确认粗大化合物为Al-Cr相,并从形成机理上对粗大金属化合物的成因进行了分析,从合金元素含量、熔铸温度、中间合金的使用等方面提出了解决措施。     

2A14合金轮毂疲劳开裂成因分析

采用光学显微镜、扫描电镜及能谱仪等检测仪器，对2A14合金轮毂锻件开裂部位进行了断口面分析、组织分析和能谱分析，讨论了疲劳开裂的成因。结果表明，2A14合金轮毂疲劳开裂是由粗大的化合物相及其聚集团引起的。同时针对开裂成因提出通过成分控制、热处理工艺优化来改善锻件中化合物的分布情况。     

功能材料Fe—Mn合金试制工艺研究

通过对功能材料Fe—Mn舍金试制过程中出现的质量问题进行探讨，得出：真空感应炉熔炼Fe—Mn合金充Ar200乇条件下，Mn收得率可按94．4％左右进行估计；Fe—Mn合金锻件由于存在局部晶粒粗大和组织不均匀，因而引起杂波探伤异常；Fe—Mn舍金加热温度1140℃±10℃，停锻温度〉1900℃，末火变形量大于30％的工艺条件下，可防止探伤杂波异常的出现。     

Er对5083合金微观组织及力学性能的影响

采用传统的铸锭冶金法制备实验合金,利用拉伸试验、金相组织观察、SEM扫描以及TEM透射等实验方法,研究了稀土元素Er对5083合金微观组织及力学性能的影响。结果表明,稀土元素Er的加入,在结晶过程中形成了一种粗大化合物,这种粗大化合物对合金的力学性能不利。     

高硅高钛铝合金铸棒粗大化合物的研究

研究了汽车防抱死系统用高硅高钛铝合金铸棒中的粗大化合物。通过宏观、微观组织分析,确定该粗大化合物为Al3Ti。Al3Ti粗大化合物的形成原因复杂,主要从合金成分、熔炼工艺和铸造工艺几个方面进行了分析,提出相应改善措施,并通过实验成功地进行了验证,消除了Al3Ti粗大化合物这一铸棒组织缺陷。     

7050合金波音锻件用铸锭铸造工艺研究

通过严格控制波音7050合金φ550mm铸锭的化学成分和熔铸工艺,解决了铸锭成型极易产生裂纺的问题,获得了小于一级晶粒度和达到双一级要求的优良冶金质量,锻件探伤合格率为100％,使波音7050合金锻坯生产实现国产化。     

9Cr2Mo、GCrl5小轧辊锻造工艺操作的改进

本文针对锻造厂快锻车间生产的9Cr2Mo、GCr15小轧辊锻件探伤合格率较低的问题，通过取样分析、讨论研究，找出了导致探伤合格率偏低的锻造主要原因，并且提出了“轧辊生产标准化操作”。通过采取合理科学有效的锻造工艺操作，提高了小轧辊锻件探伤合格率，提升了该产品的质量，为企业创造了良好的社会经济效益，占领了一定的市场份额。     

5XXX系和7XXX系铝合金中粗大金属间化合物的研究

通过试验研究了5XXX系和7XXX系合金中粗大金属间化合物的形成原因、金属间化合物对材料的影响及消除措施。     

2000t压机探伤锻件内部缺陷的产生原因及改进措施探讨

本文对锻钢厂９５年探伤锻件不合格的原因进行了分析，并从锻造的角度出发，探讨了改善锻件内部质量的有效途径。     

5E61铝合金板材折弯开裂原因分析

采用体视显微镜、扫描电子显微镜、金相显微镜对5E61-O铝合金板材的折弯开裂样品进行组织观察与分析。观察到折弯样品断口分为强剪切的裂纹起源区与传统的韧性断裂区两个部分；在样品中发现了粗大纤维晶、粗大AlTiEr化合物两种组织缺陷及其在断口中诱发的开裂、二次裂纹行为。该合金板材折弯开裂失效主要由大尺寸脆性化合物引发，需从成分设计和熔铸工艺角度入手，细化大尺寸化合物，改善折弯性能。     

稀土Y与喷射沉积技术对铝铁合金组织和性能的影响

普通凝固条件下得到的铸造Al-Fe合金中存在粗大的针状或片状初生富铁相,严重割裂基体,引起应力集中,恶化合金性能。利用稀土Y对Al-6Fe合金进行微合金化处理,结合快速凝固技术,并辅以热挤压技术,获得较常规凝固条件下更加细小均匀的显微组织,以解决铝铁合金中粗大的针片状富铁相割裂基体的问题。实验结果表明,稀土元素Y抑制了初生富铁相生长的趋势,将粗大针片状富铁相细化为菱形和短棒状,一定程度上减小了合金的第二相尺寸;稀土Y微合金化结合快速凝固技术,使得铝铁合金中形成了细小弥散的三元Al-Fe-Y金属间化合物,极大细化了第二相,在改善组织形貌的同时提升了合金的硬度和屈服强度。      

超音速气雾化高硅铝合金粉末高温加热组织及性能演变

本文利用超音速气体雾化法制备快速凝固高硅铝合金粉末，对合金粉末在不同温度加热处理后合金相组合，显微组织及显微硬度的变化特征进行系统研究。结果表明合金粉末在加热过程中，随着加热温度的升高，其组织中非平衡相逐渐转变为平衡相，同时有新的第二相沉淀析出，合金组织第二相在高温加热过程中有粗化趋势，合金显微硬度在低温加热时有下降趋势,随后升高温度不再下降，而是维持在相对稳定的水平。     

Grain refinement of AZ31 magnesium alloy by Al-Ti-C-Y master alloy

Al-Ti-C-Y master alloy was prepared by combining SHS technique and melting-casting method. The microstructure of master alloy and its grain-refining effect on AZ31 alloy were investigated by means of OM, XRD, SEM and EDS. Experimental results indicated that the prepared master alloy consisted of α-Al, TiAl3, TiC and Al3Y phases, and exhibited good grain-refining performance of AZ31 alloy. Morphology of α-Mg changed from coarse dendritic to fine equiaxed and the average grain size of α-Mg matrix reduced from the original 580 to 170 μm after adding 1.0 wt.% master alloy. The grain refining efficiency of Al-Ti-C-Y master alloy on AZ31 alloy was mainly attributed to heterogeneous nucleation of TiC particles and grain growth restriction of Al-Y compound or TiC at grain boundaries.     

高硅镁合金的制备工艺及显微组织分析

汽车发动机传动系统可采用的镁合金有AZ91D ,AM 6 0B合金[1,2 ] 。但是这些合金的抗蠕变能力较低 ,使镁合金构件与与之连接的构件间易产生旷动 ,最终导致失效。目前所开展的耐热镁合金的研究 ,其目标是在不大幅度提高成本的基础上 ,提高镁合金在 15 0～ 2 5 0℃下的高温强度和蠕变性能 ,并且具有良好的压铸性能和耐蚀性[3～ 5] 。本实验研究了高硅镁合金的熔炼制备工艺 ,分析了合金的显微组织结构。1　试验过程镁合金熔炼前首先按照实验计划进行合金的配料计算 ,然后准备炉料及所需的非金属辅助材料。将坩埚预热至暗红色 (4 0 0～ 4 5 0…     

Influence of small additives of calcium on the structure and properties of ML5 alloy (AZ91)

The influence of the calcium additive (from 0.1 to 1.0 wt %) on the phase composition and solidus temperature of ML5 magnesium alloy is investigated. Calcium transfers into the intermetallic compound of the variable composition during alloy crystallization. This compound contains Al (53.4–57.4%), Ca (42.6–42.8%), and Mg (0.002–3.8%) and is transformed with a decrease in temperature into the Al₂Ca compound. The influence of calcium on the amount of phases Mg₁₇Al₁₂ and Al₂Ca and its distribution in the casting and thermally treated ML5 alloy structures are investigated. It is revealed with the help of the electron probe microanalysis that calcium and aluminum are concentrated along the boundaries of the magnesium solid solution. It is shown that, in order to acquire satisfactory mechanical properties and pouring of calcium-containing magnesium alloys should be performed according to the production process preventing the contamination of metal of the coarse inclusions. It is established that small additives of calcium (up to 1 wt %) increase the ignition temperature and lower the alloy oxidability at elevated temperatures (up to 715°C). The influence of the sulfur hexafluoride (SF6) for the calcium loss during flux-free melting was established.     

Effects of RE on Microstructures and Mechanical Properties of Hot-Extruded AZ31 Magnesium Alloy

Effects of rare earth (RE) additions on microstructure and mechanical properties of the wrought AZ31 magnesium alloy were investigated. The results show that, by adding 0.3%, 0.6% and 1.0% RE elements, the as-cast microstructure can be refined, and the as-cast alloys‘ elongation and tensile strength can be improved. After extrusion, the alloy with 0.3 % and 0.6% RE additions obtain a finer microstructure and the best mechanical properties, but the alloy with 1.0% RE addition has the coarse A1-RE compound particles in grain boundaries which decreased elongation and tensile properties. Usually, Rare earth (RE) elements were used to improve the creep properties of aluminium-containing magnesium pressure die cast alloys at elevated temperatures. In this paper, it is also found that the high temperature strength of extruded materials can be increased by RE elements additions.     

In-situ microfracture observation of strip-cast Zr-Ti-Cu-Ni-Be bulk metallic glass alloys

In this study, Zr-Ti-Cu-Ni-Be bulk metallic glass (BMG) alloys containing a small amount of crystalline phase particles were fabricated by strip casting, and their improvement of mechanical properties and fracture toughness was explained by direct observation of the microfracture process. The compressive and fracture toughness test results indicated that strength, strain to failure, and fracture toughness of the strip-cast BMG alloy containing coarse crystalline particles were higher than those of the as-cast monolithic BMG alloy or the strip-cast BMG alloy containing fine crystalline particles. From in-situ microfracture observations, the improvement of overall mechanical properties of the strip-cast BMG alloy containing coarse crystalline particles could be interpreted by taking consideration of both the existence of coarse crystalline particles and the role of the particles to block crack propagation and to form multiple shear bands. Such property improvement suggests new applicability of the strip-cast BMG alloys containing coarse crystalline particles, which can work as toughening and strengthening reinforcements, to structures and components requiring excellent mechanical properties.     

物理破碎法改善钼粉性能对TZC钼合金顶头密度影响的研究

钼粉中普遍存在的粗大、聚集颗粒降低了钼粉的松装密度、摇实密度,使钼粉在松装时形成拱桥效应,影响钼粉的压制性能;进而在制备TZC钼合金顶头过程中直接形成粗大晶粒或因烧结长大而形成异常粗晶,造成顶头使用性能差。利用物理破碎机对钼粉进行机械粉碎试验后,消除了钼粉中的粗大、聚集颗粒,提高钼粉的松装密度、摇实密度,对改善钼粉的粒度组成分布具有非常明显的效果,进而也使钼合金顶头的密度相应得到提高。     

热轧3003合金板带材生产工艺优化

通过生产实践,依据铝及合金板带材缺陷的影响因素,确定了热轧3003合金板带材导致表面晶粒粗大的原因,优化了该产品的生产工艺制度。     

工业化制备7050铝合金厚板显微组织与力学性能

采用OM、TEM观察、室温拉伸试验,研究工业化制备大截面7050铝合金厚板微观显微组织和力学性能.结果表明:板材表层、1/4厚度层和芯部处均存在部分粗大晶粒组织以及晶粒尺寸分布不均匀现象,其中芯部粗大晶粒的尺寸、数量以及晶粒尺寸不均匀程度均高于1/4厚度层和表层;合金时效后晶内的析出相主要为η’相、η相以及少量GPⅡ区,表层晶粒内的析出相密度大于1/4层和芯部,且1/4层和芯部粗棒状的η相含量较高;合金的强度、硬度以及延伸率在厚度方向上呈梯度分布,表层硬度、抗拉强度（σ_b）、屈服强度（σ_0.2）和延伸率（δ）均最高,从表层到芯部,硬度、σ_b、σ_0.2以及δ均逐渐减小.