Effect of Solidification Rate and Rare Earth Metal Addition on the Microstructural Characteristics and Porosity Formation in A356 Alloy

Table 2

(a) Modifier additions and corresponding A356 alloy codes, graphite mold castings

Alloy	Mold type	Mold temp. (°C)	Alloy code	Modifier addition (wt.%)
				Aimed			Actual
				Sr	La	Ce	Sr	La	Ce
A356	Graphite	600	TB	0	0	0	0	0	0
			T10	0	0.2	0	0	0.165	0
			T1	0	0.5	0	0	0.356	0
			T2	0	1	0	0	0.685	0
			T3	0	1.5	0	0	1.025	0
			T11	0	0	0.2	0	0.002	0.082
			T4	0	0	0.5	0	0.006	0.185
			T5	0	0	1	0	0.006	0.317
			T6	0	0	1.5	0	0.009	1.088
			T7	0	0.5	0.5	0	0.442	0.282
			T8	0	1	1	0	0.781	0.377
			T9	0	1.5	1.5	0	1.073	0.531
			T10S	0.01	0.2	0	0.0079	0.165	0
			T1S	0.01	0.5	0	0.0109	0.356	0
			T2S	0.01	1	0	0.0077	0.685	0
			T3S	0.01	1.5	0	0.0077	1.025	0
			T11S	0.01	0	0.2	0.0073	0.002	0.182
			T4S	0.01	0	0.5	0.0078	0.006	0.358
			T5S	0.01	0	1	0.0081	0.006	0.817
			T6S	0.01	0	1.5	0.0081	0.009	1.288
			T7S	0.01	0.5	0.5	0.0083	0.442	0.382
			T8S	0.01	1	1	0.0083	0.781	0.877
			T9S	0.01	1.5	1.5	0.0089	1.073	1.231

(b) Actual Sr concentrations obtained for the step-like and variable angle mold castings of A356 alloy

Mold	Alloy code	Sr (ppm)
Step-like; mold	S12	83
	S22	95
	S32	84
	S42	105
	S52	108
	S14	79
	S24	73
	S34	77
	S44	88
	S54	89
Variable angle; mold	DBLS	127
	D10LS	79
	D1LS	109
	D2LS	74
	D3LS	74
	D11LS	73
	D4LS	70
	D5LS	71
	D6LS	77
	D7LS	75
	D8LS	78
	D9LS	70

Aimed amount was 100 ppm ± 20 ppm.