Table 2. Properties of the Ablated Component and Conventional Casting 消融法铸造零件和传统铸件的性能对比


ticles were trapped in a tight network of cell boundaries, increasing the local concen- trations of reinforcement and reducing the average interpar- ticle spacing.


Although the combina-


tion of silicon carbide and graphite particles in the liquid aluminum resulted in a near neutrally buoyant suspension, some settling and fl otation occurred over time when melting a large batch. If the melt is insuffi ciently mixed, the reinforcements can migrate, producing areas that are rich in silicon carbide or graphite. T is can result in large diff erences in the volume percentage of reinforcement in the solidifi ed microstructure. T e increase in volume percentage in the thin section of the ablated component compared to the conventional sand casting may have partly contributed to the higher strength of the ablated samples and could have been due to the casting process, if metal was ladled from the top, middle or bot- tom of the original melt charge. T e ablated samples featured an improved distribution of


10 Mean 平均值


Ablated Component 消融法零件 # 1 2 3 4 5 6 7 8


Mean 平均值


Conventional Casting 传统铸件 # 1 2 3 4 5 6 7 8 9


Tensile 拉伸强度 % Elongation 延伸率 30.6 30.7 30.3 31.2 31.2 34.1 32.5 33.2 30


0.35 0.35 0.25 0.4


0.45 0.45 0.4 0.4


31.2 31.5


Standard Deviation 标准差 1.34


0.35 0.4


0.38% 0.06


Tensile 拉伸强度 % Elongation 延伸率 38.4 41


31.6 37


35.7 36


33.2 35.6 36.1


Standard Deviation 标准差 2.91


0.35 0.4 0.3


0.25 0.4 0.3 0.3 0.3


0.33% 0.05


度，减少了颗粒间的平均 距离。


尽管铝液中的碳化硅和石 墨颗粒造成了悬浮，但大量 熔化时依然会有漂浮与沉淀 发生。如果没有对熔体进行 充分搅拌，强化相会迁移， 造成局部区域富碳化硅或石 墨颗粒。这会使最终微观组 织中强化相的体积分数波动 很大。消融铸造试样中较薄 的区域体积分数相对于传统 砂型铸造增多，进而提高了 试样强度。这应该是由于铸 造过程中金属液从熔炉中舀 出的位置不同造成的，如从 上部、中部或底部取样。 相对于传统铸造试样， 消融铸造试样的微粒分布表 现出明显不同。而且，消融 铸造似乎对晶粒尺寸也有影 响，这与之前单一A356合 金的报道是相反的。当铝液


particles in the casting compared to the conventionally cast samples. Additionally, ablation appeared to refi ne the dendritic cell size, which is in contrast to early reports in a monolithic A356 alloy. T e particulate reinforcement within the liquid melt during solidifi cation may have restricted the dendrite cell size while it was pushed by the solidifying aluminum. In ablation, the impingement of solvent on the solidifying surface increases cool- ing rates, entrapping the particles more rapidly without allowing time to substantially migrate, leading to increased branching of the dendrites and fi ner overall cell size. In the study, the samples produced via both processes


showed relatively high levels of porosity. In the ablated component, gas porosity occurred—likely due to poor gating design and a fi lling system that was not optimized for abla- tion. T e pouring technique and mold geometry should be modifi ed signifi cantly for ablation in the future since the time delay to remove the mold was signifi cant. Despite the poros- ity, the strength of the ablated sample was higher than that of the conventionally cast sample and further improvement in mechanical properties may be realized by improving the pour- ing technique to reduce turbulence in the melt (Table 2).  To receive this digital magazine in the future, go to www.globalcastingmagazine.com.


中的强化相颗粒被凝固的铝液所推挤时，也许限制了晶 粒尺寸。消融铸造法中，溶剂对凝固界面的影响加快了 冷却速度，捕获颗粒更快，使其无法充分迁移，最终增 加了晶粒的枝晶，细化了晶粒。


在试验中，两种方法的试样均表现出较高的孔隙 率。消融试验中出现了气孔——应该是由于冒口设计问 题以及充型系统并非专门为消融铸造设计。去除砂型消 耗了过多时间，因此在后续试验中，应该重新设计浇注 方式和砂型尺寸。尽管出现了气孔，消融铸造试样的强 度仍然高于传统铸造试样，而且浇注技术的改进可以降


低金属液湍流，还会带来其它机械性能的改善。 如果您想订阅我们的数字杂志， 请登陆www.globalcastingmagazine.com。


CLICK HERE for a full technical article on ablation casting.


点击这里获取更多信息 Spring 2012 FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION | 55


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72