Hf–Si system

62 accepted literature values from 2 paper(s) (experimental 24, model 21, unspecified 17); 3 calculated phase diagram(s). 1 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: JSON · CSV · interactive explorer · interactive phase diagram · phases (11) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	24
model	21
unspecified	17

Accepted values by property group
Property group	Values
invariant reaction	38
phase transition	2
phase equilibrium	1
formation	7
crystal structure	14

Calculated phase diagrams

Binary phase diagrams calculated with pycalphad 0.11.2 from the SGTE binary collection (Hallstedt 2025, CC BY 4.0). Evidence class: model.

Assessments with a calculated phase diagram
TDB file	Assessment	SHA-256	Links
HfSi-00Zha-LB.tdb	J.-C. Zhao, B.P. Bewlay, M.R. Jackson, Q. Chen, J. Phase Equilib., 21, 40-45(2000). doi:10.1361/105497100770340408	`29edae6cd520ee5ecd21bc7319503170e0c06e87814f7ec0b538a116cdc2974a`	viewer · TDB · JSON
HfSi-03Yan.tdb	Y. Yang, Y.A. Chang, J.-C. Zhao, B.P. Bewlay, Intermetallics, 11, 407-15(2003). doi:10.1016/S0966-9795(03)00021-9	`4c947308a5e5f90e20ce2fef31966e5c327be89ea8f9139bbcac842ece1718a5`	viewer · TDB · JSON
HfSi-19Hon.tdb	P. Honarmandi, T.C. Duong, S.F. Ghoreishi, D. Allaire, R. Arroyave, Acta Mater., 164, 636-47(2019). doi:10.1016/j.actamat.2018.11.007	`6640e20000baa136ef728ec703943e8f48e3ac577f918febf3c256616195ab32`	viewer · TDB · JSON

Calculated three-phase invariants (model, mole fraction of the second component)
TDB file	T (K)	Phases at the invariant
HfSi-00Zha-LB.tdb	2630	LIQUID (x(Si) 0.27716) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-00Zha-LB.tdb	2630	LIQUID (x(Si) 0.27723) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-00Zha-LB.tdb	2630	LIQUID (x(Si) 0.2773) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-00Zha-LB.tdb	2586.56	HF3SI2_D5A (x(Si) 0.4) + HF5SI4 (x(Si) 0.44444) + LIQUID (x(Si) 0.546)
HfSi-00Zha-LB.tdb	2586.56	HF3SI2_D5A (x(Si) 0.4) + HF5SI4 (x(Si) 0.44444) + LIQUID (x(Si) 0.54591)
HfSi-00Zha-LB.tdb	2405.82	HF5SI4 (x(Si) 0.44444) + HFSI_B27 (x(Si) 0.5) + LIQUID (x(Si) 0.62827)
HfSi-00Zha-LB.tdb	2405.82	HF5SI4 (x(Si) 0.44444) + HFSI_B27 (x(Si) 0.5) + LIQUID (x(Si) 0.62813)
HfSi-00Zha-LB.tdb	2405.82	HF5SI4 (x(Si) 0.44444) + HFSI_B27 (x(Si) 0.5) + LIQUID (x(Si) 0.62832)
HfSi-00Zha-LB.tdb	2358.67	LIQUID (x(Si) 0.17886) + HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375)
HfSi-00Zha-LB.tdb	2358.67	LIQUID (x(Si) 0.17878) + HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375)
HfSi-00Zha-LB.tdb	2358.67	LIQUID (x(Si) 0.17874) + HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375)
HfSi-00Zha-LB.tdb	2197.56	HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-00Zha-LB.tdb	2101.49	BCC_A2 (x(Si) 3.000e-5) + LIQUID (x(Si) 0.11111) + HF2SI_C16 (x(Si) 0.33333)
HfSi-00Zha-LB.tdb	2101.49	BCC_A2 (x(Si) 3.000e-5) + LIQUID (x(Si) 0.1111) + HF2SI_C16 (x(Si) 0.33333)
HfSi-00Zha-LB.tdb	2016	HCP_A3 (x(Si) 1.000e-5) + BCC_A2 (x(Si) 2.000e-5) + HF2SI_C16 (x(Si) 0.33333)
HfSi-00Zha-LB.tdb	1818.85	HFSI_B27 (x(Si) 0.5) + HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.80817)
HfSi-00Zha-LB.tdb	1818.85	HFSI_B27 (x(Si) 0.5) + HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.80808)
HfSi-00Zha-LB.tdb	1818.85	HFSI_B27 (x(Si) 0.5) + HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.80823)
HfSi-00Zha-LB.tdb	1597.92	HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.90793) + DIAMOND_A4 (x(Si) 1)
HfSi-00Zha-LB.tdb	1597.92	HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.90806) + DIAMOND_A4 (x(Si) 1)
HfSi-00Zha-LB.tdb	1597.92	HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.9081) + DIAMOND_A4 (x(Si) 1)
HfSi-03Yan.tdb	2626.92	LIQUID (x(Si) 0.30282) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-03Yan.tdb	2626.92	LIQUID (x(Si) 0.30294) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-03Yan.tdb	2626.92	LIQUID (x(Si) 0.303) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-03Yan.tdb	2595.12	HF3SI2_D5A (x(Si) 0.4) + HF5SI4 (x(Si) 0.44444) + LIQUID (x(Si) 0.50837)
HfSi-03Yan.tdb	2595.12	HF3SI2_D5A (x(Si) 0.4) + HF5SI4 (x(Si) 0.44444) + LIQUID (x(Si) 0.50822)
HfSi-03Yan.tdb	2416.93	HF5SI4 (x(Si) 0.44444) + HFSI_B27 (x(Si) 0.5) + LIQUID (x(Si) 0.58357)
HfSi-03Yan.tdb	2416.93	HF5SI4 (x(Si) 0.44444) + HFSI_B27 (x(Si) 0.5) + LIQUID (x(Si) 0.58352)
HfSi-03Yan.tdb	2416.93	HF5SI4 (x(Si) 0.44444) + HFSI_B27 (x(Si) 0.5) + LIQUID (x(Si) 0.58364)
HfSi-03Yan.tdb	2365.31	LIQUID (x(Si) 0.20984) + HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375)
HfSi-03Yan.tdb	2365.31	LIQUID (x(Si) 0.20971) + HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375)
HfSi-03Yan.tdb	2365.31	LIQUID (x(Si) 0.20968) + HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375)
HfSi-03Yan.tdb	2199.07	HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-03Yan.tdb	2099.95	BCC_A2 (x(Si) 1.000e-5) + LIQUID (x(Si) 0.12438) + HF2SI_C16 (x(Si) 0.33333)
HfSi-03Yan.tdb	2099.95	BCC_A2 (x(Si) 1.000e-5) + LIQUID (x(Si) 0.12433) + HF2SI_C16 (x(Si) 0.33333)
HfSi-03Yan.tdb	2016.02	HCP_A3 (x(Si) 0) + BCC_A2 (x(Si) 1.000e-5) + HF2SI_C16 (x(Si) 0.33333)
HfSi-03Yan.tdb	1814.55	HFSI_B27 (x(Si) 0.5) + HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.76149)
HfSi-03Yan.tdb	1814.55	HFSI_B27 (x(Si) 0.5) + HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.76139)
HfSi-03Yan.tdb	1814.55	HFSI_B27 (x(Si) 0.5) + HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.76151)
HfSi-03Yan.tdb	1602.75	HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.89283) + DIAMOND_A4 (x(Si) 1)
HfSi-03Yan.tdb	1602.75	HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.89285) + DIAMOND_A4 (x(Si) 1)
HfSi-03Yan.tdb	1602.75	HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.8929) + DIAMOND_A4 (x(Si) 1)
HfSi-19Hon.tdb	2740.16	LIQUID (x(Si) 0.3616) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-19Hon.tdb	2740.16	LIQUID (x(Si) 0.36052) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-19Hon.tdb	2740.15	LIQUID (x(Si) 0.36104) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-19Hon.tdb	2577.43	HF3SI2_D5A (x(Si) 0.4) + HF5SI4 (x(Si) 0.44444) + LIQUID (x(Si) 0.54873)
HfSi-19Hon.tdb	2577.43	HF3SI2_D5A (x(Si) 0.4) + HF5SI4 (x(Si) 0.44444) + LIQUID (x(Si) 0.54894)
HfSi-19Hon.tdb	2402.04	HF5SI4 (x(Si) 0.44444) + HFSI_B27 (x(Si) 0.5) + LIQUID (x(Si) 0.62957)
HfSi-19Hon.tdb	2402.04	HF5SI4 (x(Si) 0.44444) + HFSI_B27 (x(Si) 0.5) + LIQUID (x(Si) 0.62956)
HfSi-19Hon.tdb	2402.04	HF5SI4 (x(Si) 0.44444) + HFSI_B27 (x(Si) 0.5) + LIQUID (x(Si) 0.62969)
HfSi-19Hon.tdb	2224.3	LIQUID (x(Si) 0.1447) + HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375)
HfSi-19Hon.tdb	2224.3	LIQUID (x(Si) 0.14462) + HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375)
HfSi-19Hon.tdb	2224.3	LIQUID (x(Si) 0.14462) + HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375)
HfSi-19Hon.tdb	2151.35	BCC_A2 (x(Si) 0.00211) + LIQUID (x(Si) 0.12537) + HF2SI_C16 (x(Si) 0.33333)
HfSi-19Hon.tdb	2151.35	BCC_A2 (x(Si) 0.00211) + LIQUID (x(Si) 0.12537) + HF2SI_C16 (x(Si) 0.33333)
HfSi-19Hon.tdb	2013.35	HCP_A3 (x(Si) 6.700e-4) + BCC_A2 (x(Si) 0.00113) + HF2SI_C16 (x(Si) 0.33333)
HfSi-19Hon.tdb	2013.35	HCP_A3 (x(Si) 6.600e-4) + BCC_A2 (x(Si) 0.00113) + HF2SI_C16 (x(Si) 0.33333)
HfSi-19Hon.tdb	1816.93	HF2SI_C16 (x(Si) 0.33333) + HF5SI3_D88 (x(Si) 0.375) + HF3SI2_D5A (x(Si) 0.4)
HfSi-19Hon.tdb	1807.63	HFSI_B27 (x(Si) 0.5) + HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.80902)
HfSi-19Hon.tdb	1807.63	HFSI_B27 (x(Si) 0.5) + HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.80888)
HfSi-19Hon.tdb	1807.63	HFSI_B27 (x(Si) 0.5) + HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.80903)
HfSi-19Hon.tdb	1609.18	HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.90012) + DIAMOND_A4 (x(Si) 1)
HfSi-19Hon.tdb	1609.18	HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.90034) + DIAMOND_A4 (x(Si) 1)
HfSi-19Hon.tdb	1609.18	HFSI2_C49 (x(Si) 0.66667) + LIQUID (x(Si) 0.90041) + DIAMOND_A4 (x(Si) 1)
HfSi-19Hon.tdb	383.39	HF2SI_C16 (x(Si) 0.33333) + HF3SI2_D5A (x(Si) 0.4) + HF5SI4 (x(Si) 0.44444)

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull HfSi-00Zha-LB · CALPHAD hull HfSi-03Yan

Invariant reactions (literature)

Invariant reactions reported in the literature for the Hf–Si system (38)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location	Quote
2753.15	congruent melting: L->Hf3Si2	L: Si 0.4; Hf3Si2: Hf 0.6, Si 0.4	experimental	[1] Yang 2003 cites Brukl 1968	Table 3, p. 3, row 21 report
2736.15	congruent melting: L->Hf3Si2	L: Si 0.4; Hf3Si2: Hf 0.6, Si 0.4	model	[1] Yang 2003	Table 3, p. 3, row 20 report
2633.15	L+Hf3Si2->Hf5Si3	Hf3Si2: Hf 0.6, Si 0.4; Hf5Si3: Hf 0.625, Si 0.375	experimental	[1] Yang 2003 cites Brukl 1968	Table 3, p. 3, row 7 report
2633.15	peritectic: L + Hf3Si2 -> Hf5Si3	Hf3Si2: Si 0.4; Hf5Si3: Si 0.375	model	[2] Zhao 2000	Table 2, p. 2, row 7 report
2630.15	peritectic: L + Hf3Si2 -> Hf5Si3	L: Si 0.277; Hf3Si2: Si 0.4; Hf5Si3: Si 0.375	model	[2] Zhao 2000	Table 2, p. 2, row 8 report
2628.15	L+Hf3Si2->Hf5Si3	L: Si 0.303; Hf3Si2: Si 0.4; Hf5Si3: Si 0.375	model	[1] Yang 2003	Table 3, p. 3, row 6 report
2594.15	L+Hf3Si2->Hf5Si4	L: Si 0.509; Hf3Si2: Si 0.4; Hf5Si4: Si 0.444	model	[1] Yang 2003	Table 3, p. 3, row 10 report
2593.15	peritectic: Hf3Si2 + L -> Hf5Si4	Hf3Si2: Si 0.4; Hf5Si4: Si 0.444444	experimental	[2] Zhao 2000 cites ref. 68Bru	Table 2, p. 2, row 13 report
2593.15	L+Hf3Si2->Hf5Si4	Hf3Si2: Hf 0.6, Si 0.4; Hf5Si4: Hf 0.555556, Si 0.444444	experimental	[1] Yang 2003 cites Brukl 1968	Table 3, p. 3, row 11 report
2586.15	peritectic: Hf3Si2 + L -> Hf5Si4	Hf3Si2: Si 0.4; L: Si 0.546; Hf5Si4: Si 0.444444	model	[2] Zhao 2000	Table 2, p. 2, row 14 report
2418.15	L+Hf5Si4->HfSi	L: Si 0.583; Hf5Si4: Si 0.444; HfSi: Si 0.5	model	[1] Yang 2003	Table 3, p. 3, row 12 report
2415.15	L+Hf5Si4->HfSi	Hf5Si4: Hf 0.555556, Si 0.444444; HfSi: Hf 0.5, Si 0.5	experimental	[1] Yang 2003 cites Brukl 1968	Table 3, p. 3, row 13 report
2415.15	peritectic: Hf5Si4 + L -> HfSi	Hf5Si4: Si 0.444444; HfSi: Si 0.5	experimental	[2] Zhao 2000 cites ref. 68Bru	Table 2, p. 2, row 15 report
2406.15	peritectic: Hf5Si4 + L -> HfSi	Hf5Si4: Si 0.444444; L: Si 0.628; HfSi: Si 0.5	model	[2] Zhao 2000	Table 2, p. 2, row 16 report
2365.15	L+Hf5Si3->Hf2Si	L: Si 0.21; Hf5Si3: Si 0.375; Hf2Si: Si 0.333	model	[1] Yang 2003	Table 3, p. 3, row 3 report
2359.15	L+Hf5Si3->Hf2Si	L: Si 0.179; Hf5Si3: Si 0.375; Hf2Si: Si 0.333	model	[1] Yang 2003 cites Zhao 2000 doi	Table 3, p. 3, row 4 report
2359.15	peritectic: L + Hf5Si3 -> Hf2Si	L: Si 0.179; Hf5Si3: Si 0.375; Hf2Si: Si 0.333333	model	[2] Zhao 2000	Table 2, p. 2, row 6 report
2356.15	L+Hf5Si3->Hf2Si	Hf5Si3: Hf 0.625, Si 0.375; Hf2Si: Hf 0.666667, Si 0.333333	experimental	[1] Yang 2003 cites Brukl 1968	Table 3, p. 3, row 5 report
2356.15	peritectic: L + Hf5Si3 -> Hf2Si	Hf5Si3: Si 0.375; Hf2Si: Si 0.333333	experimental	[2] Zhao 2000 cites ref. 68Bru	Table 2, p. 2, row 5 report
2198.15	eutectoid: Hf5Si3 -> Hf2Si + Hf3Si2	Hf5Si3: Si 0.375; Hf2Si: Si 0.333333; Hf3Si2: Si 0.4	experimental	[2] Zhao 2000	Table 2, p. 2, row 9 report
2198.15	Hf5Si3->Hf2Si+Hf3Si2	Hf5Si3: Si 0.375; Hf2Si: Si 0.333; Hf3Si2: Si 0.4	model	[1] Yang 2003	Table 3, p. 3, row 8 report
2198.15	Hf5Si3->Hf2Si+Hf3Si2	Hf5Si3: Hf 0.625, Si 0.375; Hf2Si: Hf 0.666667, Si 0.333333; Hf3Si2: Si 0.4	experimental	[1] Yang 2003 cites Brukl 1968	Table 3, p. 3, row 9 report
2198.15	eutectoid: Hf5Si3 ↔ Hf2Si + Hf3Si2		experimental	[2] Zhao 2000	p. 3 report	Based on the above data, it is clear that the eutectoid reaction, Hf5Si3 ↔ Hf2Si + Hf3Si2, exists at 1925 ± 25 °C.
2197.15	eutectoid: Hf5Si3 -> Hf2Si + Hf3Si2	Hf5Si3: Si 0.375; Hf2Si: Si 0.333333; Hf3Si2: Si 0.4	model	[2] Zhao 2000	Table 2, p. 2, row 10 report
2104.15	eutectic: L->bcc(Hf)+Hf2Si	L: Si 0.115; Hf2Si: Hf 0.666667, Si 0.333333	experimental	[1] Yang 2003 cites Brukl 1968	Table 3, p. 3, row 2 report
2104.15	eutectic: L -> bcc (Hf) + Hf2Si	L: Si 0.115; Hf2Si: Si 0.333333	experimental	[2] Zhao 2000 cites ref. 68Bru	Table 2, p. 2, row 1 report
2101.15	eutectic: L -> bcc (Hf) + Hf2Si	L: Si 0.111; Hf2Si: Si 0.333333	model	[2] Zhao 2000	Table 2, p. 2, row 2 report
2100.15	eutectic: L->bcc(Hf)+Hf2Si	L: Si 0.12; bcc(Hf): Si 0; Hf2Si: Si 0.333	model	[1] Yang 2003	Table 3, p. 3, row 1 report
2016.15	peritectoid: Bcc (Hf) + Hf2Si -> hcp (Hf)	Hf2Si: Si 0.333333	model	[2] Zhao 2000	Table 2, p. 2, row 4 report
2016.15	peritectoid: Bcc (Hf) + Hf2Si -> hcp (Hf)	Hf2Si: Si 0.333333	experimental	[2] Zhao 2000 cites ref. 68Bru	Table 2, p. 2, row 3 report
1819.15	peritectic: HfSi + L -> HfSi2	HfSi: Si 0.5; L: Si 0.808; HfSi2: Si 0.666667	model	[2] Zhao 2000	Table 2, p. 2, row 18 report
1816.15	peritectic: HfSi + L -> HfSi2	HfSi: Si 0.5; HfSi2: Si 0.666667	experimental	[2] Zhao 2000 cites ref. 68Bru	Table 2, p. 2, row 17 report
1816.15	L+HfSi->HfSi2	HfSi: Hf 0.5, Si 0.5; HfSi2: Hf 0.333333, Si 0.666667	experimental	[1] Yang 2003 cites Brukl 1968	Table 3, p. 3, row 15 report
1814.15	L+HfSi->HfSi2	L: Si 0.762; HfSi: Si 0.5; HfSi2: Si 0.667	model	[1] Yang 2003	Table 3, p. 3, row 14 report
1603.15	eutectic: L->HfSi2+(Si)	L: Si 0.91; HfSi2: Hf 0.333333, Si 0.666667	experimental	[1] Yang 2003 cites Brukl 1968	Table 3, p. 3, row 17 report
1603.15	eutectic: L -> HfSi2 + diamond_A4 (Si)	L: Si 0.91; HfSi2: Si 0.666667; diamond_A4 (Si): Si 1	experimental	[2] Zhao 2000 cites ref. 68Bru	Table 2, p. 2, row 19 report
1603.15	eutectic: L->HfSi2+(Si)	L: Si 0.893; HfSi2: Si 0.667; (Si): Si 1	model	[1] Yang 2003	Table 3, p. 3, row 16 report
1598.15	eutectic: L -> HfSi2 + diamond_A4 (Si)	L: Si 0.908; HfSi2: Si 0.666667; diamond_A4 (Si): Si 1	model	[2] Zhao 2000	Table 2, p. 2, row 20 report

Formation enthalpies

Literature values in kJ/mol-atom where the per-atom basis is known. DFT columns: the lowest-energy entry at the same composition (Materials Project 2026.04.13, OQMD v1.8; different energy references, never averaged), from dft_parity.json.

Enthalpies of formation, Hf–Si system (7)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location
Hf2Si	Hf2Si	-62.7 kJ/mol-atom	298.15	unspecified	-69.475 (mp-aaaaaosg)	-71.646 (oqmd-7793)	[2] Zhao 2000 cites Samsonov 1980 doi	Table 3, p. 3, row 1 report
Hf3Si2	Hf3Si2	-80 kJ/mol-atom ± 4.7	1473	experimental	-74.298 (mp-aaaaadcz)	-77.301 (oqmd-647083)	[2] Zhao 2000 cites Topor 1990 doi	Table 3, p. 3, row 9 report
Hf5Si3	Hf5Si3	-70.2 kJ/mol-atom	298.15	unspecified	-69.268 (mp-aaaaaxqb)	-71.886 (oqmd-647084)	[2] Zhao 2000 cites Samsonov 1980 doi	Table 3, p. 3, row 5 report
Hf5Si3	Hf5Si3	-70.2 kJ/mol-atom ± 3.3	298.15	experimental	-69.268 (mp-aaaaaxqb)	-71.886 (oqmd-647084)	[2] Zhao 2000 cites Golutvin 1971	Table 3, p. 3, row 4 report
HfSi	HfSi	-71.1 kJ/mol-atom	298.15	unspecified	-75.502 (mp-aaaaaboc)	-79.13 (oqmd-647082)	[2] Zhao 2000 cites Samsonov 1980 doi	Table 3, p. 3, row 13 report
HfSi	HfSi	-71.1 kJ/mol-atom ± 4.6	298.15	experimental	-75.502 (mp-aaaaaboc)	-79.13 (oqmd-647082)	[2] Zhao 2000 cites Golutvin 1971	Table 3, p. 3, row 12 report
HfSi	HfSi	-70.9 kJ/mol-atom ± 2	1473	experimental	-75.502 (mp-aaaaaboc)	-79.13 (oqmd-647082)	[2] Zhao 2000 cites Meschel 1998 doi	Table 3, p. 3, row 15 report

Other properties

Phase transition (2)

Phase transition, Hf–Si system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase transition	2753.15 K	2753.15	congruent melting: L -> Hf3Si2 L: Si 0.4; Hf3Si2: Si 0.4	model	[2] Zhao 2000	Table 2, p. 2, row 12 report
Phase transition	2753.15 K	2753.15	congruent melting: L -> Hf3Si2 L: Si 0.4; Hf3Si2: Si 0.4	experimental	[2] Zhao 2000 cites ref. 68Bru	Table 2, p. 2, row 11 report

Phase equilibrium (1)

Phase equilibrium, Hf–Si system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase assemblage		2223.15	Hf5Si3 + Hf2Si alloy: Si 0.35	experimental	[2] Zhao 2000	p. 3 report	The microstructure of the Hf-35at.%Si annealed at 1950 °C consisted mostly of the Hf5Si3 and Hf2Si, as shown in Fig. 2.

Crystal structure (14)

Crystal structure, Hf–Si system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Lattice a	6.553 Å	298.15	Hf2Si alloy: Si 0.333333	unspecified	[2] Zhao 2000 cites Havinga 1972 doi	Table 1, p. 2, row 1 report
Lattice a	6.988 Å	298.15	Hf3Si2 alloy: Si 0.4	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 3 report
Lattice a	7.844 Å	298.15	Hf5Si3 alloy: Si 0.375	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 2 report
Lattice a	7.039 Å	298.15	Hf5Si4 alloy: Si 0.444444	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 4 report
Lattice a	6.889 Å	298.15	HfSi alloy: Si 0.5	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 5 report
Lattice a	3.672 Å	298.15	HfSi2 alloy: Si 0.666667	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 6 report
Lattice b	3.772 Å	298.15	HfSi alloy: Si 0.5	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 5 report
Lattice b	14.57 Å	298.15	HfSi2 alloy: Si 0.666667	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 6 report
Lattice c	5.186 Å	298.15	Hf2Si alloy: Si 0.333333	unspecified	[2] Zhao 2000 cites Havinga 1972 doi	Table 1, p. 2, row 1 report
Lattice c	3.675 Å	298.15	Hf3Si2 alloy: Si 0.4	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 3 report
Lattice c	5.492 Å	298.15	Hf5Si3 alloy: Si 0.375	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 2 report
Lattice c	12.83 Å	298.15	Hf5Si4 alloy: Si 0.444444	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 4 report
Lattice c	5.223 Å	298.15	HfSi alloy: Si 0.5	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 5 report
Lattice c	3.641 Å	298.15	HfSi2 alloy: Si 0.666667	unspecified	[2] Zhao 2000 cites Karpinsky 1969	Table 1, p. 2, row 6 report

Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

Y Yang, Y.A Chang, J.-C Zhao, B.P Bewlay, Thermodynamic modeling of the Nb–Hf–Si ternary system, Intermetallics 11, 407-415 (2003). doi:10.1016/s0966-9795(03)00021-9
J. -C. Zhao, B. P. Bewlay, M. R. Jackson, Q. Chen, Hf-Si binary phase diagram determination and thermodynamic modeling, JPE 21, 40-45 (2000). doi:10.1361/105497100770340408

Please cite

R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735569
R. Arróyave, J. Saal, D. Shin, ORCHID-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735859
R. Arróyave, J. Saal, D. Shin, ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD) (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735891
R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23736065

Also cite the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work); B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, https://doi.org/10.1016/j.calphad.2025.102833 (CC BY 4.0), and the original assessment named in each file; A. Jain et al., The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002, https://doi.org/10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501, https://doi.org/10.1007/s11837-013-0755-4 and S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010, https://doi.org/10.1038/npjcompumats.2015.10 (CC BY 4.0). Version 1, machine-extracted: values were read by language-model readers constrained to quote their source and checked automatically, and the release was then audited on the printed pages by adversarial audits, an independent second review of fit-facing records and a preliminary human review of a frozen sample. Flags such as accepted and ESPEI-ready record screening results, not certification; known issues are listed in the release notes.

@misc{orchid_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_phase_diagrams_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Diagrams: calculated binary phase diagrams}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735859},
  url       = {https://doi.org/10.5281/zenodo.23735859}
}

@misc{orchid_hulls_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD)}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735891},
  url       = {https://doi.org/10.5281/zenodo.23735891}
}

@misc{orchid_data_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID data: umbrella record of the ORCHID datasets}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23736065},
  url       = {https://doi.org/10.5281/zenodo.23736065},
  note      = {Version 1, machine-extracted}
}