Appendix 1

This appendix gives an idea of the structures of various equiatomic and nonequiatomic HEA solid solutions. The HEAs have been grouped according to their structures.

Table A1.1

HEAs with BCC Structure

Composition	Processing Route	Reference
Equiatomic Alloys
AlFeTi	MA	Varalakshmi et al. (2008)
CrTiV	MaS	Tsai et al. (2010b)
HfNbZr	Sputtering	Guo et al. (2013c) and Nagase et al. (2013)
AlCrFeTi	MA	Varalakshmi et al. (2008)
MoNbTaW	AM	Senkov et al. (2010, 2011b) and Widom et al. (2013)
AlCoCrFeNi	MA	Ji et al. (2014)
AlCoCrFeNi	SC	Wang et al. (2009b) and Qiao et al. (2011)
AlCoCrFeNi	AM	Wang et al. (2008) and Zhou et al. (2008b)
AlCoCrFeNi	BS	Zhang et al. (2012b)
AlCoCrNiSi	GTAW cladding	Lin and Cho (2008)
AlCoCrFeNi	Electro-spark deposition	Li et al. (2013c)
AlCoFeNiTi	AM	Wang et al. (2012c)
AlCrFeTiZn	MA	Varalakshmi et al. (2008)
HfNbTaTiZr	AM and HIP	Senkov et al. (2011a, 2012a)
HfNbTiVZr	AM	Sobol et al. (2012)
MoNbTaVW	AM	Senkov et al. (2010, 2011b)
AlCoCrCuFeNi	MA	Tariq et al. (2013) and Zhang et al. (2009b,c)
AlCoCrCuFeNi	Splat quenching	Singh et al. (2011b)
AlCrCuFeTiZn	MA	Varalakshmi et al. (2008, 2010a)
AlCoCuNiTiZn	MA	Varalakshmi et al. (2010b,c)
CrCoFeMnNiW	MA	Varalakshmi et al. (2008)
AlCoCrCuFeNiW	MA	Tariq et al. (2013)
AlCoCrCuFeNiWZr	MA	Tariq et al. (2013)
Nonequiatomic Alloys
AlCoCrCu0.5Ni	Sputtering	Yeh et al. (2004b)
AlCoCrCu0.5Ni	AM	Yeh et al. (2004b)
AlxCoCrFeNi (x=0.9–2)	AM	Wang et al. (2012b)
Al0.7Co0.3CrFeNi	MA	Chen et al. (2013b)
Al0.5CoFeNiSi0.5	AM and SC	Zhang et al. (2012d)
AlxCoFeNiSi (x>0.3)	AM	Zhang et al. (2013b)
AlxCrFe1.5MnNi0.5 (x=0.8–1.2)	AM	Tsai et al. (2013c)
Al0.5CrMoNbTi	AM	Liu et al. (2014)
MoNbV0.5TiZr	SC	Zhang et al. (2012c)
AlCoCrCuxFeNi	AM	Zhang et al. (2010d)
AlCoCrCu0.5FeNi	AM	Tung et al. (2007)
AlCoCrCu0.25FeNi	IC	Zhang et al. (2008b)
AlCoCrFeMoxNi (x=0 and 0.1)	AM	Zhu et al. (2010a)
AlCoCrFeNbxNi (x=0–0.1)	AM	Zhang et al. (2012c)
AlCoCrFeNiSix (x=0–0.8)	AM	Zhu et al. (2010b)
Al0.5CrFe1.5MnNi0.5	AM	Tang et al. (2010)
Al0.5CrMoNbTiV	AM	Liu et al. (2014)
AlCoCrFe6NiSiTi	LC	Zhang et al. (2011b,c,d)
AlCrFeMo0.5NiSiTi	Plasma spray	Huang et al. (2004)
AlCoCrFeMo0.5NiSiTi	Plasma spray	Huang et al. (2004)
Al2CoCrCuFeMnNiTiV	AM	Zhang et al. (2008a)

Table A1.2

HEAs with FCC Structure

Composition	Processing Route	Reference
Equiatomic Alloys
CoCuNi	MA	Varalakshmi et al. (2010b)
CoFeNi	DC	Guo et al. (2014)
CoFeNi	IM	Singh and Subramaniam (2014)
CoFeNi	AM	Wang et al. (2012c)
CoFeNi	MA	Praveen et al. (2012, 2013b)
CoCrFeNi	DC	Guo et al. (2014)
CoCrCuNi	MA	Durga et al. (2012)
CoCuFeNi	MA	Praveen et al. (2012, 2013b)
CoCuNiZn	MA	Varalakshmi et al. (2010b)
CoFeMnNi	MA	Praveen et al. (2013b)
AlCoCuNiZn	MA	Varalakshmi et al. (2010b)
CoCrCuFeNi	AM	Cui et al. (2011b) and Li et al. (2009)
CoCrCuFeNi	LC	Zhang et al. (2011e) and Cheng et al. (2013)
CoCrFeMnNi	IM	Ye et al. (2012)
CoCrFeMnNi	AM	Bhattacharjee et al. (2014), Gali and George (2013), and Zaddach et al. (2013)
CoCrFeMnNi	DC	Liu et al. (2013), Otto et al. (2013a), and Zhu et al. (2013)
CoCrFeMnNi	MeS	Cantor et al. (2004)
CoCrFeMnNi	MA	Zaddach et al. (2013)
CoCrFeNiTi	AM	Zhang et al. (2009a)
CoCuFeNiTi	AM	Wang et al. (2012c)
CoCuFeNiV	IC	Zhang et al. (2008b)
CrCuFeMoNi	AM	Li et al. (2009)
CrTiVYZr	MaS	Tsai et al. (2010b)
AlCoCrCuFeNi	MaS	Dolique et al. (2009, 2010)
CoCrFeMnNiCu	MeS	Cantor et al. (2004)
CoCrFeMnNiNb	MeS
CoCrFeMnNiV	MeS
Nonequiatomic Alloys
Al0.5CoCrFeNi	AM	Lin and Tsai (2011)
Al0.3CoCrFeNi	AM and BS	Ma et al. (2013a)
Al0.3CoCrFeNi	AM	Shun et al. (2010a,b)
Al0.5CoCrFeNi	IC	Zhang et al. (2008b)
AlxCoCrFeNi (x=0–0.3)	AM	Wang et al. (2014b)
AlxCoCrFeNi (x=0–0.4)	AM	Wang et al. (2012b)
AlxCoCrFeNi (x=0–0.45)	AM	Kao et al. (2011)
AlxCoCrFeNi (x=0–0.65)	AM	Tian et al. (2013a)
Al0.25CoCrFeNi	AM	Kao et al. (2009)
AlxCoCrFeNi (x=0–0.375)	AM	Chou et al. (2009)
AlxCoFeNiSix (x<0.3)	AM	Zhang et al. (2013b)
AlxCoFeNiSi0.2	AM and SC	Zhang et al. (2012d)
Al0.2CoFeNiSi0.2	AM and IM	Zuo et al. (2013)
AlxCrCuFeNi2 (x≤0.5)	DC	Guo et al. (2013b)
Al0.5CrCuFeNi2	SC	Ma et al. (2013b)
CoCrCu0.5FeNi	AM	Hsu et al. (2005)
CoCrFeMo0.3Ni	AM	Shun et al. (2010a, 2012a)
CoCrFeNiTi0.3	AM	Shun et al. (2012b)
CoCuFeNiSnx (x=0–0.05)	AM	Liu et al. (2012)
CrCu2Fe2Ni2Mn	AM	Ren et al. (2010, 2012)
Cr2CuFe2Mn2Ni2	AM
CrCuFeMn2Ni2	AM
AgCoCuFeNi Ptx	RF Sputtering	Tsai et al. (2009a)
AlxCoCrCu1−xFeNi	AM	Zhang et al. (2010d)
Al0.5CoCrCuFeNi	AM	Yeh et al. (2004b)
Al0.5CoCrCuFeNi	Sputtering	Chen et al. (2004)
AlxCoCrCuFeNi	RF Sputtering	Yeh et al. (2004a)
AlxCoCrCuFeNi	AM	Tong et al. (2005b)
AlxCoCrCuFeNi	AM	Wu et al. (2006)
Al0.5CoCrCuFeNi	AM	Tung et al. (2007)
AlxCoCrCu1−xFeNi	AM	Zhou et al. (2008b)
AlxCoCrCuFeNi	AM	Tang and Yeh (2009)
Al0.5CoCrCuFeNi	AM	Tsai et al. (2009b)
Al0.5CoCrCu0.5FeNi	AM	Li et al. (2013a)
Al0.3CoCrCu0.5FeNi	AM	Tsai et al. (2013e)
Al0.5CoCrCu0.5FeNi2	IM	Daoud et al. (2013)
Alx(CoCrFeMnNi)100−x (x<8 at.%)	AM	He et al. (2014)
Al0.3CoCrFeMo0.1Ni	AM	Shun et al. (2010a,b)
AlxCoCrFeMo0.5Ni (x=0–0.5)	AM	Hsu et al. (2013a,b)
Al0.3CoCrFeNiTi0.1	AM	Shun et al. (2010b)
AlxCo1.5CrFeNiTiy	AM	Chuang et al. (2011)
AlxCoCrFeNiTi0.5 (x=0,0.2)	AM	Dong et al. (2013b)
AlCoCuxNiTiZn	MA	Varalakshmi et al. (2010b)
Al0.5CoCrFeMnNi	AM	Pauzi et al. (2013)
AlxCoCrCu1−xFeNiTi0.5 (x=0, 0.25)	SC	Wang et al. (2009a)
Al0.5CoCrCuFeNiVx (x<0.4)	AM	Chen et al. (2006a)
Co1.5CrFeNi1.5Ti0.5Mox (x=0,0.1)	AM	Chou et al. (2010b)

Table A1.3

HEAs Showing More Than One Solid Solution

Composition	Processing Route	Major Phase	Minor Phase	Reference
Equiatomic Compositions
AlCuNi	AM	BCC	FCC	Yeh et al. (2007a)
CrFeNi	IM	FCC	BCC	Singh and Subramaniam (2014)
AlCoCuNi	AM	BCC	FCC	Yeh et al. (2007a)
CoCrFeNi	MA	FCC	BCC	Praveen et al. (2012)
CoFeNiTi	AM	HCP	FCC	Tsau (2009)
CoCrFeNi	MA	FCC	BCC	Praveen et al. (2013b)
CoCuFeNi	IM	FCC1	FCC2	Singh and Subramaniam, (2014)
AlCoCrCuNi	GTAW cladding	FCC	BCC	Lin and Cho (2009)
AlCoCrCuNi	AM	BCC	FCC	Yeh et al. (2007a)
AlCoCrCuFe	LC	FCC	BCC	Qiu et al. (2013)
AlCoCuFeNi	AM	BCC	FCC	Zhuang et al. (2013)
AlCoCuFeNi	SC	BCC	FCC	Zhuang et al. (2012)
AlCrCuFeNi	AM	BCC	FCC	Li et al. (2009)
CoCrCuFeNi	MA	FCC	BCC	Praveen et al. (2012, 2013b)
CrCuFeMnNi	AM	FCC	BCC	Li et al. (2009) and Ren et al. (2010, 2012)
AlCoCrCuFeNi	Plasma spraying	BCC	FCC	Yue et al. (2013)
AlCoCrCuFeNi	Powder metallurgy	FCC	BCC	Qiu (2013)
AlCoCrCuFeNi	IM	BCC	FCC1+FCC2	Kuznetsov et al. (2012, 2013) and Singh et al. (2011b)
AlCoCrCuFeNi	SC	BCC	FCC	Zhuang et al. (2012)
AlCoCrCuFeNi	LC	BCC	FCC	Yue et al. (2014)
AlCoCrCuFeNi	AM	BCC	FCC	Tung et al. (2007), Yeh et al. (2007a), and Wen et al. (2009)
AlCoCrCuFeNi	AM	FCC	BCC	Wu et al. (2006)
AlCoCrCuFeNi	MaS	BCC	FCC	Dolique et al. (2010)
AlCoCuFeNiTi	AM	BCC	FCC	Wang et al. (2012c)
AlCoCuFeNiTi	SC	BCC	FCC	Zhuang et al. (2012)
AlCrCuFeNiZn	MA	BCC	FCC	Pradeep et al. (2013) and Koundinya et al. (2013)
AlCoCrCuFeMnNi	AM	BCC	FCC	Li et al. (2008a)
AlCoCrCuFeNiTi	AM	BCC1	BCC2, FCC
AlCoCrCuFeNiV	AM	BCC	FCC
AlCoCrCuFeNiSi	AM	BCC	FCC	Yeh et al. (2007a)
AlCrCuFeNbNiTi	AM	FCC1+FCC2	BCC	Razuan et al. (2013)
CoCrFeNiCuAlTiXVMo (X=Zn, Mn)	MA	BCC	FCC	Fazakas et al. (2013)
Nonequiatomic Compositions
NbTiV2Zr	AM	BCC2	BCC1+BCC3	Senkov et al. (2013b)
AlxCoCrFeNi	AM	x=0.5–0.75: FCC	BCC	Chou et al. (2009)
		x=0.875–1: BCC	FCC
AlxCoCrFeNi (x=0.5,0.75)	AM	FCC	BCC	Kao et al. (2009)
Al0.3CrFe1.5MnNi0.5	AM	FCC	BCC	Tang et al. (2009)
Al0.3CrFe1.5MnNi0.5	AM	FCC	BCC	Chen et al. (2010a)
Al0.5CrCuFeNi2	DC	FCC1	FCC2	Ng et al. (2014)
Al0.3CrFe1.5MnNi0.5	AM	BCC	FCC	Tang et al. (2012)
Al0.3CrFe1.5MnNi0.5	AM	FCC1	BCC+FCC2	Tsao et al. (2012)
AlxCoCrFeNi (x=0.5–0.8)	AM	FCC	BCC	Wang et al. (2012b)
Al0.75CoCrCu0.25FeNiTi0.5	SC	BCC	BCC	Wang et al. (2009a)
Al0.3CoFeNiSi0.3	AM	FCC	BCC	Zhang et al. (2013b)
AlxCoCrFeNi (x=0.45–0.85)	AM	FCC	BCC	Kao et al. (2011)
Al0.3CrFe1.5MnNi0.5	IM	FCC	BCC	Chuang et al. (2013)
AlCrCuFeNi2	SC	FCC	BCC	Ma et al. (2013b)
Al0.3CoFeNiSi0.3	AM	FCC	BCC	Zhang et al. (2013b)
Al0.5CoCrCuFeNiVx (x=0.4–2)	AM	FCC	BCC	Chen et al. (2006a)
Co0.5CrFeNiTi0.5	MA	BCC	FCC	Fu et al. (2013b)
CrCuxFeTiZny (x/y=1/0, 3/1, 1 and x+y=40)	MA	FCC	BCC	Mridha et al. (2013)
Cr2Cu2FeNi2Mn	AM	FCC	BCC	Ren et al. (2010, 2012)
Cr2Cu2FeNiMn2	AM	FCC	BCC
CrCu2Fe2NiMn2	AM	FCC	BCC
Cr2CuFe2NiMn	AM	FCC	BCC
Al0.8CoCrCuFeNi	AM	FCC	BCC	Tong et al. (2005b)
AlCo0.5CrCuFeNi	AM	FCC	BCC	Tung et al. (2007)
AlCoCr0.5CuFeNi	AM	FCC	BCC
AlCoCrCuFe0.5Ni	AM	FCC	BCC
AlCoCrCuFeNi0.5	AM	FCC	BCC
Al0.75CoCrCu0.25FeNi	AM	BCC	FCC	Zhou et al. (2008b)
AlCoCrFeNiTix (x=0.5, 1)	IC	BCC1	BCC2	Zhou et al. (2007b)
AlCoxCrFeNiTi0.5	SC	x=1: BCC1	BCC2	Wang and Zhang (2008)
		x=1.5, 2, 3: BCC	FCC
AlCoCuxNiTiZn	MA	x=0: BCC	FCC	Varalakshmi et al. (2010b)
		x=8.33: BCC	FCC
		x=50: FCC	BCC
AlxCoCrCu1−xFeNi (x=0.25–0.75)	AM	FCC	BCC	Zhang et al. (2010d)
Al0.5C0.2Co0.3CrFeNi	MA	BCC	FCC	Fang et al. (2014)
Alx(CoCrFeMnNi)100−x (x=8–16 at.%)	AM	FCC	BCC	He et al. (2014)
AlCoCrCuxNiTi (x=0.5–0.8)	AM	FCC	BCC	Wang et al. (2012a)
Al0.8CoCrCuFeNi	DC	FCC1+FCC2	BCC	Liu et al. (2011)
AlxCoCrCuFeNi (x=1–2)	LC	BCC	FCC	Ye et al. (2011)
AlxCoCrFeNiTi0.5 (x=0.8–1)	AM	BCC1	BCC2	Dong et al. (2013b)
CoNiFeCrAl0.6Ti0.4	MA	BCC	FCC	Fu et al. (2013a)
AlxFeCoNiCrCu0.5	AM	x=1: BCC	FCC1	Li et al. (2013a)
		x=1.5: BCC	FCC2
Al0.5CoCrFeCuNi	IM	FCC1	FCC2 (Cu rich)	Sheng et al. (2013)
AlxCoCrCuFeNi (x=0.45,1)	MA	FCC1+FCC2	BCC	Sriharitha et al. (2013)
CoCrFeMnNiZrx (x=0–0.3)	AM	BCC	FCC	Pauzi et al. (2013)
AlCuCrFeNiTix	AM	x=0: FCC1	BCC1	Razuan et al. (2013)
		x=0.5, 1: BCC1+FCC1	BCC2
		x=1.5: BCC1+BCC2	FCC1
AlCuCrFeNiNbx	AM	x=0: FCC1	BCC1
		x=0.5: FCC1+FCC2	BCC1
		x=1, 1.5: FCC1+FCC2+BCC1	BCC2
Al2CoCrFeMo0.5Ni	AM	BCC2	BCC1	Hsu et al. (2013a,b)
AlCoCrCuFe2Mo0.2Ni	MA	BCC	FCC	Yuhu et al. (2013)
AlCoCrCuxFeNiTi0.5 (x=0, 0.25, 0.5)	IC	BCC1	BCC2	Zhou et al. (2008c)
Al0.5CoCrCu0.5FeNiTi0.5	SC	FCC	BCC	Wang et al. (2009a)
Al2CoCrCuFeNi	LC	BCC	FCC	Qiu et al. (2014)
AlCoCrCuFeNiTix	AM	x=0.5: BCC1+FCC	BCC2	Hongfei et al. (2011)
		x=1: BCC1+FCC	BCC2
Al2CoCrCuFeNixTi (x=0–1.0)	LC	FCC	BCC	Qiu and Liu (2013)
Al0.5CoCrFeMnNiZrx (x=0.1–0.3)	AM	BCC	FCC	Pauzi et al. (2013)
Al11.1(CoCrCuFeMnNiTiV)88.9	IM	FCC	BCC	Zhou et al. (2007a)
CoCuyFeNiTix	AM	FCC1 (Cu rich)+FCC2 (Co rich) (x=1/3, 3/7, 3/5)	BCC (β-Ti rich) (x=3/5)	Mishra et al. (2012)
CoCuyFeNiTix (x/y=1/3, 3/7, 3/5, 9/11, 11/9, 3/2)	SC	FCC1	FCC2	Samal et al. (2014)
AlCoCrFeNiTix (x=0–2)	AM	BCC1	BCC2	Zhang et al. (2008a)
AlxCoCrFeNiTi (x=1–2)	AM	BCC	B2	Zhang et al. (2009a)

AM, arc melting; IM, induction melting; IC, injection casting; SC, suction casting; BS, Bridgman solidification; MeS, melt spinning; LENS, laser engineered net shaping; LC, laser cladding; MA, mechanical alloying; MaS, magnetron sputtering.