热处理对3D打印Inconel 718合金组织和力学性能的影响研究

发布时间：2018-03-09 19:29

本文选题：Inconel　切入点：718合金　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：Inconel 718合金构件的传统制造工艺为锻造,而相比传统的锻造成形工艺,3D打印技术具有生产周期短、易于制备复杂零件以及生产成本低等特点,因此本文采用3D打印的激光选区熔化(SLM)工艺制备了Inconel 718合金/TiC纳米颗粒增强Inconel 718合金构件,并对该合金进行了固溶处理、固溶+时效处理,研究了不同热处理工艺下合金组织演变规律和δ相、γ"相和γ′相等析出相析出规律。研究了析出相和TiC纳米颗粒添加与合金力学行为(抗拉强度、维氏硬度和延伸率)的关联关系,并分析了相关影响机制。主要结论如下:SLM成形Inconel 718合金沉积态组织中存在似椭圆状痕迹,其大小不一,具有明显方向性;椭圆状组织由柱状晶组成。合金经940℃~1100℃固溶后,柱状晶转变为等轴细晶,组织可析出两种形貌特征δ相:短棒状和针状,δ相的化学式为Ni3Nb。在固溶温度为940℃~980℃时,在晶界可析出短棒状δ相,而晶内析出针状δ相,且断口表面存在大小不均的韧窝和少量孔洞、裂纹源,明显表现为塑性断裂特征。固溶温度超过1000℃时,晶内针状δ相基本消失,主要为晶界处短棒状δ相析出,数量明显减少,且断口处韧窝相比固溶温度较低时增多增大。短棒状δ相析出可阻碍合金在拉伸塑性变形过程中的位错运动,是合金在940℃~980℃固溶后其抗拉强度和维氏硬度明显高于沉积态的主要因素之一。合金在固溶温度为1020℃~1100℃时,组织中晶粒与固溶温度为940℃~980℃时相比明显粗化,且因有害相Laves相基本溶解和枝晶偏析现象得到改善,合金延伸率有所提高。合金在620-720℃时效处理后在晶内析出大量弥散分布的针状δ相,以及圆盘状γ"相和细小黑点状γ′相。γ"和γ′相与基体γ相共格,可产生显著的共格强化效果,是合金经时效处理后抗拉强度显著提高的主要原因之一。合金添加TiC颗粒后,其沉积态组织中柱状晶粒更细小,且在热处理过程中其组织中析出相与未添加TiC时具有相似的析出规律。由于TiC颗粒与基体结合良好,在相同热处理工艺条件下与未添加TiC相比,合金因TiC颗粒的强化作用,其抗拉强度明显提高。
[Abstract]:The traditional manufacturing process of Inconel 718 Alloy Components for forging, and compared with the traditional forging technology, 3D printing technology has a short production cycle, easy preparation of complex parts and low production cost, so this paper uses the selective laser melting of 3D printing (SLM) technology for preparation of Inconel 718 Alloy /TiC nano particle reinforced Inconel 718 Alloy the component, and the alloy solid solution treatment, solid solution and aging treatment of different heat treatment on the microstructure evolution process and gamma delta phase, and gamma prime precipitates "equal precipitation was studied. The precipitates and adding TiC nanoparticles and alloy mechanical behavior (tensile strength, hardness and elongation of Vivtorinox the rate of) the association, and analyzed the influence mechanism. The main conclusions are as follows: SLM forming elliptical trace exists Inconel 718 Alloy Deposited in its size, has the obvious direction ; elliptical tissue is composed of columnar crystal alloy. By 940 DEG ~1100 DEG after solid solution, the columnar to equiaxed grains, the organization can be separated two kinds of morphology of delta phase: short rod and acicular, chemical formula of delta phase Ni3Nb. in the solution temperature is 940 DEG ~980 DEG. Precipitation of short rod Delta phase at the grain boundaries, and the precipitation of intragranular acicular delta phase, and the fracture surface has uneven size of dimples and a small hole, crack source is obviously plastic fracture characteristics. The solution temperature more than 1000 DEG C, intragranular acicular 5-stabilized disappeared, mainly in the grain boundary of short rod delta phase precipitation, significantly reduce the number of fracture and dimple compared to solid solution at low temperature increase. Short rod delta phase precipitation can hinder dislocation motion in the alloy tensile plastic deformation process, is one of the main factors of the alloy at 940 DEG ~980 DEG solution after the tensile strength and hardness was higher than Vivtorinox deposited. Gold in the solution temperature is 1020 DEG ~1100 DEG C, in grain coarsening compared with solid solution temperature of 940 DEG ~980 DEG C, and due to the harmful Laves phase basic dissolution and dendrite segregation phenomenon has been improved, the elongation of the alloy is improved. The alloy after aging treatment at 620-720 DEG C in amorphous precipitate the dispersed phase and the disc delta needle, "and small black spots like gamma gamma prime. Gamma and gamma prime phase and matrix phase coherent gamma, can produce significant precipitation strengthening effect, is one of the main reasons of alloy after aging tensile strength increased significantly. The alloy added TiC particles after its deposition in the microstructure of columnar grain is finer, and in the process of heat treatment and precipitation in the tissue without the addition of TiC has the similar rule. Due to the precipitation of TiC particles and matrix is good, in the same heat treatment conditions compared with those without adding TiC, because TiC alloy particles The tensile strength is obviously improved.

【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG132.3;TG166.7

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